Microsoft C#.Net Tutorials

noreply@blogger.com (fdfsdf) — Tue, 08 Apr 2014 05:46:00 +0000

TEXTBOX CONTROL

Used to take any user input in the application.
API: System.Windows.Forms.TextBox

Property of TextBox

Property	Description
Name	Specifies the name of the control.
Text	Specifies the displayable text of the control.
BackColor	Specifies the background color of the control.
ForeColor	Specifies the foreground color of the control.
Font	Specifies the font style of the control‘s text.
Enabled	Enables / Disables the control.
Visible	Displays / Hides the control.
Cursor	Specifies the mouse pointer style, when it is over on the control.
Size	Specifies the Width and Height of the control.
Location	Specifies the X and Y co-ordinations of the control‘s position on the form.
TextAlign	Specifies the position of the text in the control (Left / Center / Right)
Image	Specifies the image that is to be displayed in the control along with the text.
ImageAlign	Specifies the position of the image in the control
TabIndex	Specifies the index of the control in the tab order.
ContextMenuStrip	Contains the reference of the respective context menu control.
ReadOnly	Enables / disables read-only nature of the textbox. In the read only textbox, the user can not enter any text.
MultiLine	Enables / disables multiple lines in the text box. By default, the text box will be single-line textbox.
WordWrap	This is used in multi line textboxes, which automatically moves the cursor to the next line, when the current line exceeds.
Scrollbars	Enables / disables scroll bars in the textbox.
PasswordChar	Used to specify the password display character. Ex: *
MaxLength	Specifies the maximum no. of characters that can be entered in the textbox.

Property of Event of TextBox

Event	Description
TextChanged	Executes when any character is typed / removed in the textbox.
Click	Executes when the user clicks the control run time.
DoubleClick	Executes when the user double-clicks the control at run time.
MouseMove	Executes when the mouse pointer is moves across the control.
MouseEnter	Executes when the mouse pointer is focused on to the control.
MouseLeave	Executes when the mouse pointer is out of the button.
KeyPress	Executes when any key is pressed on the keyboard, while the focus is on the control.
Enter	Executes when the focus is entered into the control.
Leave	Executes when the focus is out of the control.

Method of TextBox

Method	Description
Clear()	Clears all the contents of the textbox and makes it empty
Focus()	Moves the focus to the control.

Program for Demo Textbox

<html>
 <head>
  <script type="text/javascript">
   window.onload = functionundefined)
   {
     document.getElementByIdundefined'send').onclick = functionundefinede)
    {
     Name :  alertundefineddocument.getElementByIdundefined"name").value);
     return false;
    }
   }
  </script>
 </head>
<body>
 <form method="post">
  <div align="left">
   <input id="name" name="name" type="text" />
   <input id="send" name="send" type="submit" value="send" />
  </div>
 </form>
</body>
</html>

private void btnOK_Clickundefinedobject sender, EventArgs e)
 {
  string name = txtName.Text;
  string message = name;
  lblMessage.Text = message;
  lblMessage.Visible = true;
 }

noreply@blogger.com (fdfsdf) — Tue, 08 Apr 2014 05:39:00 +0000

Label Control

Mainly used for presentation purpose, to display a message or description to the user.

API: System.Windows.Forms.Label

Properties of Label

Property	Description

Text	Specifies the displayable text of the control.
BackColor	Specifies the background color of the control.
ForeColor	Specifies the foreground color of the control.
Font	Specifies the font style of the control‘s text.
Enabled	Enables / Disables the control.
Visible	Displays / Hides the control.
Cursor	Specifies the mouse pointer style, when it is over on the control.
Size	Specifies the Width and Height of the control.
Location	Specifies the X and Y co-ordinations of the control‘s position on the form.
TextAlign	Specifies the position of the text in the control (Left / Center / Right)
Image	Specifies the image that is to be displayed in the control along with the text.
ImageAlign	Specifies the position of the image in the control
TabIndex	Specifies the index of the control in the tab order.
ContextMenuStrip	Contains the reference of the respective context menu control.
AutoSize	Enables / disables automatic sizing of the control, based on the text.

Events of Label

Event	Description
Click	Executes when the user clicks the control run time.
DoubleClick	Executes when the user double-clicks the control at run time.
MouseMove	Executes when the mouse pointer is moves across the control.
MouseEnter	Executes when the mouse pointer is focused on to the control.
MouseLeave	Executes when the mouse pointer is out of the button.
KeyPress	Executes when any key is pressed on the keyboard, while the focus is on the control.
Enter	Executes when the focus is entered into the control.
Leave	Executes when the focus is out of the control.

noreply@blogger.com (fdfsdf) — Tue, 08 Apr 2014 05:27:00 +0000

Button Control

It is known as action based control. Executes an operation, when it is clicked.

API: System.Windows.Forms.Button

Properties of Button

Property	Description
Name	Specifies the name of the control.
Text	Specifies the displayable text of the control.
BackColor	Specifies the background color of the control.
ForeColor	Specifies the foreground color of the control.
Font	Specifies the font style of the control‘s text.
Enabled	Enables / Disables the control.
Visible	Displays / Hides the control.
Cursor	Specifies the mouse pointer style, when it is over on the control.
Size	Specifies the Width and Height of the control.
Location	Specifies the X and Y co-ordinations of the control‘s position on the form.
TextAlign	Specifies the position of the text in the control (Left / Center / Right)
Image	Specifies the image that is to be displayed in the control along with the text.
ImageAlign	Specifies the position of the image in the control
TabIndex	Specifies the index of the control in the tab order.
ContextMenuStrip	Contains the reference of the respective context menu control.
FlatStyle	Specifies style of the button. (Flat / Popup / Standard / System).

Events of Button

Event	Description
TextChanged	Executes when any character is typed / removed in the textbox.
Click	Executes when the user clicks the control run time.
DoubleClick	Executes when the user double-clicks the control at run time.
MouseMove	Executes when the mouse pointer is moves across the control.
MouseEnter	Executes when the mouse pointer is focused on to the control.
MouseLeave	Executes when the mouse pointer is out of the button.
KeyPress	Executes when any key is pressed on the keyboard, while the focus is on the control.
Enter	Executes when the focus is entered into the control.
Leave	Executes when the focus is out of the control.

C# Controls

noreply@blogger.com (fdfsdf) — Mon, 07 Apr 2014 18:12:00 +0000

List of Windows Form Controls :

Button

Label

TextBox

CheckBox,

RadioButton,

LinkLable,

PictureBox,

Panel,

GroupBox,

ListBox,

ComboBox,

NumericUpDown,

DomainUpDown,

Date Time Picker,

Month Calender,

Track Bar,

Timer,

Progress Bar,

Menu Strip,

Context Menu Strip,

Color Dialog,

Font Dialog,

FolderBrowserDialog,

OpenFileDialog,

SaveFileDialog,

PrintDialog,

RichTextBox,

NotifyIcon,

TabControl,

TreeView,

Working With Multi Form

noreply@blogger.com (fdfsdf) — Sat, 05 Apr 2014 08:48:00 +0000

Working With Multi Form

Adding a new Form to the Project:

In the Solution Explorer, right click on the project and choose Add --> Windows Form.
In the dialog box, enter the name of the new form.
Then the new form will be created.

Deleting a Form from the Project:

In the Solution Explorer, right click on the required form, which you want to delete and click on Delete option.
Click on OK for confirmation.

Changing Startup Form:

Even, if you add multiple forms to the project, when the project is started, the Form1will be opened by default. This is called as Startup form.
To change the startup form, change the following statement with the required class name in the Program class‘s Main() method.

Syn: Application.Run(new <form name>());

Ex: Application.Run(new Form2());

Invoke Forms at Run Time (Programmatically):

To open any form at run time programmatically, you require to create an object for the form class.

FormName obj = new FormName();

obj.Show()

Program for Multi Form Handling

/*Form1.cs
---------------------------------------*/
 private void Form1_DoubleClick(object sender, EventArgs e)
  {
   Form2 f = new Form2();
   f.Show();
  }

System.Windows.Forms.Form Class

The System.Windows.Forms.Form offers few properties, methods and events for each user-defined form class.

Method	Description
Name	Specifies the name of the form class.
Text	Specifies the title bar text of the form.
ShowIcon	Specifies whether the form icon is to be displayed or not.
ShowInTaskBar	Specifies whether the task bar icon is to be displayed or not.
MinimizeBox	Specifies whether the minimize button is to be displayed or not.
MaximizeBox	Specifies whether the maximize button is to be displayed or not.
HelpButton	Displays / hides the ? button in the form title bar.
ControlBox	Specifies whether the control box is to be displayed or not. Here the control box means minimize, maximize and close buttons.
Enabled	Activates / Deactivates the functionality of the entire form.
AutoScroll	Enables / Disables automatic activation of scrollbars in the form.
TopMost	Enables / Disables automatic activation of scrollbars in the form.
TopMost	Activates / de-activates the nature of "Always on top"
IsMDIContainer	When it is true, the form acts as Parent form.
BackColor	Specifies the background color of the form.
ForeColor	Specifies default foreground color for all the controls of this form.
Font	Specifies default font for all the controls of this form.
BackgroundImage	Specifies the background image of the form. It requires an image file of any image format.
BackgroundImageLayout	Specifies mode of the background image. (None / Tile / Center / Stretch / Zoom)
Icon	Specifies the icon of the form, displayed at left most side of the form title bar. It equires icon file with ".ico" file.
WindowState	Specifies the status of the form window. (Normal / Minimized / Maximized)
Cursor	Specifies the mouse cursor style. (Arrow, Hand etc.)
FormBorderStyle	None / FixedSingle / Fixed3D / FixedDialog / Sizable / FixedToolWindow / SizableToolWindow
Size (Width and Heght)	Specifies the size of the form (pixels format).
Location (X and Y)	Specifies the position of the form (pixels format).
Opacity	Specifies form graphics depth percentage. (1% to 100%)

Syntax to access the Properties at run time: this.Property = value;
While you are changing the property values, you remember and follow the following syntaxes:

Assign Property value at runtime in Window Form Class

Property	Statement to assign the value at run time
Name	Not possible to change at run time.
Text	this.Text = "xxxxxxxxxx";
ShowIcon	this.ShowIcon = true / false;
ShowInTaskBar	this.ShowInTaskbar = true / false;
MinimizeBox	this.MinimizeBox = true / false;
MaximizeBox	this.MaximizeBox = true / false;
HelpButton	this.HelpButton = true / false;
ControlBox	this.ControlBox = true / false;
Enabled	this.Enabled = true / false;
AutoScroll	this.AutoScroll = true / false;
TopMost	this.TopMost = true / false;
IsMDIContainer	this.IsMdiContainer = true / false;
BackColor	this.BackColor = System.Drawing.Color.xxxxxxx;
ForeColor	this.ForeColor = System.Drawing.Color.xxxxxxx;
Font	this.Font = new System.Drawing.Font("font name", size);
BackgroundImage	this.BackgroundImage = System.Drawing.Image.FromFile("image file path");
BackgroundImageLayout	this.BackgroundImageLayout = System.Windows.Forms.ImageLayout.xxxxx
Icon	this.Icon = new System.Drawing.Icon("icon file path");
WindowState	this.WindowState = System.Windows.Forms.FormWindowState.Normal; (or) this.WindowState = System.Windows.Forms.FormWindowState.Minimized; (or) this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
Cursor	this.Cursor = System.Windows.Forms.Cursors.xxxxx;
FormBorderStyle	this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.xxxxx;
Size (Width and Heght)	this.Size = new System.Drawing.Size(width, height);
Location (X and Y)	this.Location = new System.Drawing.Point(x, y);
Opacity	this.Opacity = n;

Methods of “System.Windows.Forms.Form” Class

Property	Description
Hide()	Makes the form invisible at run time.
Show()	Makes the form visible at run time.
Close()	Closes the form.

Syntax to access the Methods in the code: this.Method();

Events of “System.Windows.Forms.Form” Class

Method	Description
Load	Executes whenever the form is loaded in the memory at run time, before the form is displayed on the screen.
Shown	Executes after the form is displayed on the screen.
FormClosing	Executes when the form is about to be closed.
FormClosed	Executes after the form is closed.
Click	Executes when the user clicks on the form at run time
DoubleClick	Executes when the user double-clicks on the form at run time.
MouseMove	Executes when the mouse pointer is moves across the form.
MouseEnter	Executes when the mouse pointer is focused on to the form.
MouseLeave	Executes when the mouse pointer is out of the form.
Move	Executes when the form is moved at run time, using keyboard or mouse.
Resize	Executes when the form is resized at run time.
KeyPress	Executes when any key is pressed on the keyboard, while running on the form.
Enter	Executes when the focus is got into the form.
Leave	Executes when the focus is out of the form.

Program for Windows Form Events

private void Form1_Loadundefinedobject sender, EventArgs e)
  {
  this.Text = "This is load event.";
  }
  private void Form1_Moveundefinedobject sender, EventArgs e)
  {
   this.Text = "This is move event.";
  }
  private void Form1_Clickundefinedobject sender, EventArgs e)
   {
    this.Text = "This is click event.";
   }
  private void Form1_DoubleClickundefinedobject sender, EventArgs e)
   {
    this.Text = "This is double click event.";
   }
  private void Form1_FormClosedundefinedobject sender, FormClosedEventArgs e)
   {
    MessageBox.Showundefined"Bye. Thank you.");
   }
  private void Form1_Resizeundefinedobject sender, EventArgs e)
   {
    this.Text = "This is resize event.";
   }
  private void Form1_KeyPressundefinedobject sender, KeyPressEventArgs e)
   {
    this.Text = "This is key press event.";
   }

Program for Window Form Properties

private void Form1_Clickundefinedobject sender, EventArgs e)
{
 this.Text = "Thanks for clicking";
 this.BackColor = Color.Green;
 this.WindowState = FormWindowState.Maximized;
}

Program Demo for Windows Form Properties

 
private void btnRed_Clickundefinedobject sender, EventArgs e)
 {
 this.BackColor = Color.Red;
 }
 private void btnGreen_Clickundefinedobject sender, EventArgs e)
 {
 this.BackColor = Color.Green;
 }
 private void btnBlue_Clickundefinedobject sender, EventArgs e)
 {
  this.BackColor = Color.Blue;
 }

Program Demo for Windows Form Properties

private void btnNormal_Clickundefinedobject sender, EventArgs e)
 {
 this.WindowState = FormWindowState.Normal;
 }
 private void btnMinimize_Clickundefinedobject sender, EventArgs e)
 {
 this.WindowState = FormWindowState.Minimized;
 }
 private void btnMaximize_Clickundefinedobject sender, EventArgs e)
 {
 this.WindowState = FormWindowState.Maximized;
 }
 private void btnExit_Clickundefinedobject sender, EventArgs e)
 {
 this.Closeundefined);
 }

Program Demo for Windows Form Properties

private void btnShowBackgroundImage_Clickundefinedobject sender, EventArgs e)
 {
  this.BackgroundImage = Image.FromFileundefined"c:\\globe.jpg");
  this.BackgroundImageLayout = ImageLayout.Zoom;
 }
 private void btnClearBackgroundImage_Clickundefinedobject sender, EventArgs e)
 {
  this.BackgroundImage = null;
 }

Event Handling

noreply@blogger.com (fdfsdf) — Sat, 05 Apr 2014 07:28:00 +0000

Event Handling

Def: The event handling includes with executing some code, whenever the user performs an action.

The necessary code is to be written in a special method. That method is called as Event Handler.

Event Handler:

An event handler is a method, which will be called automatically, whenever the user performs certain event at run time.
The event handler should be defined in the form class.

Syntax:

private void controlname_eventname(object sender, EventArgs e)
      {
         //some code
      }

In the above syntax, there are two arguments:

sender: Represents the control, based on which the event is raised. For example, in the "button1_click" event handler, the sender argument represents button1 control.

e: Contains some additional information about the event. For example, in the MouseClick event, the position of the mouse will be represented, where it is clicked.

Event through you know the syntax of event handler properly, don‘t try to type it manually in the code. The event handler method should be generated through the proper way.
In the previous examples, you have generated the event handlers by double clicking on the controls.
But already you know that, for all the controls, there are multiple events. But when you double click the control, it will generate the event handler for only one event. That particular event can be called as Default event.
For example, the default event for the button is Click event.
If you want to implement the event handlers for other controls, you require to follow the steps given below.

Implementation of Event Handler:

First, in the design window, select the form or control, for which you want to create the event handler.
Open Properties window, and click on Events option.
Select the required event, for which you want to create the event handler.
Press Enter.
Then the event handler will be created in the code window.

Demo on Event Handling

private void button1_Clickundefinedobject sender, EventArgs e)
 {
  MessageBox.Showundefined"You have clicked the button");
 }
private void button1_MouseEnterundefinedobject sender, EventArgs e)
 {
  button1.BackColor = Color.Yellow;
  button1.ForeColor = Color.DarkRed;
 }
 private void button1_MouseLeaveundefinedobject sender, EventArgs e)
 {
  button1.BackColor = Color.DarkRed;
  button1.ForeColor = Color.Yellow;
 }

Change Property Value at Run Tiime

noreply@blogger.com (fdfsdf) — Sat, 05 Apr 2014 07:11:00 +0000

Change Property Value at Run Time

You can change the property values at run time (programmatically).
For example, you have designed a button with blue background. Later, after the user clicks it, you want to display that button with green background.
Then you require to change the BackColor property value at run time.
Syntax:
controlname.property = value;
Ex:
button1.Text = Button is clicked
But sometimes, when you are trying to change some property values, you may face some problems.
For example, the following statements are not valid statements:

button1.BackColor = green;

button1.Cursor = hand;

button1.TextAlign = TopLeft;

So, while you are changing the property values, you remember and follow the following syntaxes:

Assign Property Values at Run Time

Property	STATEMENT TO ASSIGN THE VALUE AT RUN TIME
Name	Not possible to change at run time
Text	controlname.Text = "xxxxx";
Enabled	controlname.Enabled = true / false;
Visible	controlname.Visible = true / false;
Location	controlname.Location = new System.Drawing.Point(x, y);
Size	controlname.Size = new System.Drawing.Size(width, height);
Font	controlname.Font = new System.Drawing.Font("font name", fontsize);
BackColor	controlname.BackColor = System.Drawing.Color.xxxxx;
ForeColor	controlname.ForeColor = System.Drawing.Color.xxxxx;
Cursor	controlname.Cursor = System.Windows.Forms.Cursors.xxxxx;
Image	controlname.Image = System.Drawing.Image.FromFile("image file path");
TextAlign	controlname.TextAlign = System.Drawing.ContentAlignment.MiddleRight;
ImageAlign	controlname.TextAlign = System.Drawing.ContentAlignment.MiddleRight;
TabIndex	controlname.TabIndex = n;
ContextMenuStrip	controlname.ContextMenuStrip = xxxxx;

Demo on Changing Property Values at Run Time

private void button2_Click(object sender, EventArgs e)
 {
  button1.Text = "My Test Button";
 }
 private void button3_Click(object sender, EventArgs e)
 {
  button1.Enabled = false;
 }
 private void button4_Click(object sender, EventArgs e)
 {
  button1.Enabled = true;
 }
 private void button5_Click(object sender, EventArgs e)
 {
  button1.Visible = false;
 }
 private void button6_Click(object sender, EventArgs e)
 {
  button1.Visible = true;
 }
 private void button7_Click(object sender, EventArgs e)
 {
  button1.Location = new Point(150, 400);
 }
 private void button8_Click(object sender, EventArgs e)
 {
  button1.Size = new Size(250, 100);
 }
 private void button9_Click(object sender, EventArgs e)
 {
  button1.Font = new Font("Showcard Gothic", 17);
 }
 private void button10_Click(object sender, EventArgs e)
 {
  button1.BackColor = Color.LightCoral;
 }
 private void button11_Click(object sender, EventArgs e)
 {
  button1.ForeColor = Color.Green;
 }
 private void button12_Click(object sender, EventArgs e)
 {
  button1.Image = Image.FromFile("c:\\flagindia.gif");
  button1.ImageAlign = ContentAlignment.MiddleLeft;
  button1.TextAlign = ContentAlignment.MiddleRight;
  button1.Size = new Size(200, 60);
 }

Control Handling Windows Form

noreply@blogger.com (fdfsdf) — Sat, 05 Apr 2014 06:59:00 +0000

Next : Change Property value at Run Time

Control Handling Windows Form

Common Properties for all the controls:

The following properties commonly available for all the controls:

Common Properties

Property	Description
Name	Specifies the name of the control.
Text	Specifies the displayable text of the control.
BackColor	Specifies the background color of the control.
ForeColor	Specifies the foreground color of the control.
Font	Specifies the font style of the control‘s text.
Enabled	Enables / Disables the control.
Visible	Displays / Hides the control.
Cursor	Specifies the mouse pointer style, when the mouse is over on the control at run time.
Runtime
Size	Specifies the Width and Height of the control.
Location	Specifies the X and Y co-ordinations of the control‘s position on the form.
TextAlign	Specifies the position of the text in the control.
Image	Specifies the image that is to be displayed in the control along with the text.
ImageAlign	Specifies the position of the image in the control
TabIndex	Specifies the index of the control in the tab order.
ContentMenuStrip	Contains the reference of the respective context menu control.

COMMON EVENTS FOR ALL THE CONTROLS:

The following events commonly available for all the controls:

COMMON EVENTS

Event	Description
Click	Executes when the user clicks the control run time.
DoubleClick	Executes when the user double-clicks the control at run time.
MouseMove	Executes when the mouse pointer is moves across the control.
MouseEnter	Executes when the mouse pointer is focused on to the control.
MouseLeave	Executes when the mouse pointer is out of the control.
KeyPress	Executes when any key is pressed on the keyboard, while the focus is on the control.
Enter	Executes when the focus is entered into the control.
Leave	Executes when the focus got out of the control.

Event: An event is a run time action that can be performed by the user.
Let us practice the above properties and events on the button control.

Demo on Buttons

Take a new Windows Forms Application project.
Design the form as follows:
To design the form as above set the following properties

Double click on Button1 and Write the following code:

private void button1_Click(object sender, EventArgs e)
{
      DateTime dt = DateTime.Now;
      MessageBox.Show(dt.ToString());
}

Double click on Button2 and Write the following code:

private void button2_Click(object sender, EventArgs e)
{
   Random r = new Random();
   int n = r.Next(1, 500);
   MessageBox.Show(n.ToString());
}

Double click on Button3 and Write the following code:

private void button3_Click(object sender, EventArgs e)
{
   MessageBox.Show("Bye....");
  Application.Exit();
}

Next : Change Property value at Run Time

LINQ With Lambda Expressions

noreply@blogger.com (fdfsdf) — Wed, 02 Apr 2014 15:20:00 +0000

LINQ With Lambda Expressions

LINQ queries can be written in two syntaxes:
1. General Query Syntax
2. Lambda Expression Syntax
The previously written applications are written with General Query Syntax.
Syntax for Lambda Expression:

DataSource.Clause(DataAliasName => Expression)

Ex: stu.Where(s => s.Marks < 300)

Program with LINQ to LAMBDA EXPRESSIONS

Student.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace LINQtoObjectsDemo
{
   class Student
    {
      //fields
        public int StudentID;
        public string Name;
        public string Course;
        public int Marks;
     //constructor
        public Student(int StudentID, string Name, string Course, int Marks)
         {
            this.StudentID = StudentID;
            this.Name = Name;
            this.Course = Course;
            this.Marks = Marks;
        }
    }
}

Program.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace LINQwithLambaExpressions
{
  class Program
   {
     static void Main(string[] args)
      {
        //data source
          Student[] stu = { new Student(101, "Prakash", "MBA", 765),
                                    new Student(102, "Pradeep", "MBA", 471),
                                    new Student(103, "Pushpa", "Msc", 590),
                                    new Student(104, "Purna", "MCA", 223),
                                     new Student(105, "Purnima", "MCA", 450)};
       //linq query with where clause
         IEnumerable result1 = stu.Where(s => s.Course == "MCA");
         Console.WriteLine("MCA Students:");
         foreach (Student r in result1)
         Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
       //linq query with compound where clause
         IEnumerable result2 = stu.Where(s => s.Name.EndsWith("a") && s.Marks >= 400 &&                                                                 s.Marks <= 600);
         Console.WriteLine("\nStudents whose name ends with 'a', and marks is >=400 and <=600:");
         foreach (Student r in result2)
         Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
       //linq query with orderby clause
         IEnumerable result4 = stu.OrderBy(s => s.Marks);
         Console.WriteLine("\nStudents (sort on marks):");
         foreach (Student r in result4)
         Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
       //linq query with orderby clause (descending)
         IEnumerable result5 = stu.OrderByDescending(s => s.Marks);
         Console.WriteLine("\nStudents (sort on marks - descending):");
         foreach (Student r in result5)
         Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
       //linq query with group clause
         IEnumerable> result6 = stu.GroupBy(s => s.Course);
          Console.WriteLine("\nStudents with grouping:");
          foreach (IGrouping> StuGrp in  result6)
           {
             Console.WriteLine(StuGrp.Key + ":");
              foreach (Student r in StuGrp)
             Console.WriteLine(" " + r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
            }
            Console.Read();
        }
    }
}

Previous Page : LINQ

Development of Form

noreply@blogger.com (fdfsdf) — Mon, 31 Mar 2014 16:05:00 +0000

Development of Form

It includes with two stages:

Designing
Coding

1) Designing the Form:

Drag and Drop the controls from the ToolBox.
A Sample Windows Application Project (with Login Form)

Select the control and set the properties as your wish.
For example, set the following properties as per given below:

Form1

Text: Login

Label1

Text: User Name

Label2

Text: Password

TextBox1

(No properties are required in this example)

TextBox2

PasswordChar: *

Button1

Text: OK

Button2

Text: Cancel

2) Coding the Form:

Double click on the controls and write the code in the Code window.
For example, double click on OK button and write the following code:

private void button1_Click(object sender, EventArgs e)
{
   if (textBox1.Text == "system" && textBox2.Text == "manager")
   MessageBox.Show("Login is successful.");
   else
   MessageBox.Show("Invalid Login.");
}

And then, double click on ―Cancel‖ button and write the following code:

private void button2_Click(object sender, EventArgs e)
{
  Application.Exit();
}

The above process is called as Form coding.

Every Form is a Class:

C#.NET recognizes every form as a class.
In VB 6.0, every form is known as an object for the Form class. But in C#, every form is a class; so that at run time, you can create a ny no. of objects as your wish. For example, if you want to display Login form twice at run time, you can simply create two objects and can show it.

The Automatic Generated Code:

While you design the controls, the Visual Studio generates some automatic code in the “Form1.Designer.cs” file.
To open this file, Open Solution Explorer, Expand Form1, then double click on Form1.Designer.cs.
For example, you can see the automatic generated code for the previous Login example

Default.aspx.cs:

namespace WindowsFormsApplication1
{
partial class Form1
{
/// 
/// Required designer variable.
/// 
private System.ComponentModel.IContainer components = null;
/// 
/// Clean up any resources being used.
/// 
/// true if managed resources should be disposed; 
otherwise, false.
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
#region Windows Form Designer generated code
/// 
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// 
private void InitializeComponent()
{
 this.textBox1 = new System.Windows.Forms.TextBox();
 this.textBox2 = new System.Windows.Forms.TextBox();
 this.button1 = new System.Windows.Forms.Button();
 this.button2 = new System.Windows.Forms.Button();
 this.label1 = new System.Windows.Forms.Label();
 this.label2 = new System.Windows.Forms.Label();
 this.SuspendLayout();
// 
// textBox1
// 
 this.textBox1.Location = new System.Drawing.Point(186, 44);
 this.textBox1.Margin = new System.Windows.Forms.Padding(5, 4, 5, 4);
 this.textBox1.Name = "textBox1";
 this.textBox1.Size = new System.Drawing.Size(232, 27);
 this.textBox1.TabIndex = 0;
// 
// textBox2
// 
 this.textBox2.Location = new System.Drawing.Point(186, 102);
 this.textBox2.Margin = new System.Windows.Forms.Padding(5, 4, 5, 4);
 this.textBox2.Name = "textBox2";
 this.textBox2.PasswordChar = '*';
 this.textBox2.Size = new System.Drawing.Size(232, 27);
 this.textBox2.TabIndex = 1;
// 
// button1
// 
 this.button1.Location = new System.Drawing.Point(186, 167);
 this.button1.Margin = new System.Windows.Forms.Padding(5, 4, 5, 4);
 this.button1.Name = "button1";
 this.button1.Size = new System.Drawing.Size(107, 37);
 this.button1.TabIndex = 2;
 this.button1.Text = "OK";
 this.button1.UseVisualStyleBackColor = true;
 this.button1.Click += new System.EventHandler(this.button1_Click); 

// 
// button2
// 
 this.button2.Location = new System.Drawing.Point(314, 167);
 this.button2.Margin = new System.Windows.Forms.Padding(5, 4, 5, 4);
 this.button2.Name = "button2";
 this.button2.Size = new System.Drawing.Size(107, 37);
 this.button2.TabIndex = 3;
 this.button2.Text = "Cancel";
 this.button2.UseVisualStyleBackColor = true;
 this.button2.Click += new System.EventHandler(this.button2_Click);
// 
// label1
// 
 this.label1.AutoSize = true;
 this.label1.Location = new System.Drawing.Point(64, 48);
 this.label1.Margin = new System.Windows.Forms.Padding(5, 0, 5, 0);
 this.label1.Name = "label1";
 this.label1.Size = new System.Drawing.Size(104, 19);
 this.label1.TabIndex = 4;
 this.label1.Text = "User Name:";
// 
// label2
// 
 this.label2.AutoSize = true;
 this.label2.Location = new System.Drawing.Point(64, 107);
 this.label2.Margin = new System.Windows.Forms.Padding(5, 0, 5, 0);
 this.label2.Name = "label2";
 this.label2.Size = new System.Drawing.Size(93, 19);
 this.label2.TabIndex = 5;
 this.label2.Text = "Password:";
// 
// Form1
// 
 this.AutoScaleDimensions = new System.Drawing.SizeF(10F, 19F);
 this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
 this.ClientSize = new System.Drawing.Size(492, 244);
 this.Controls.Add(this.label2);
 this.Controls.Add(this.label1);
 this.Controls.Add(this.button2);
 this.Controls.Add(this.button1);
 this.Controls.Add(this.textBox2);
 this.Controls.Add(this.textBox1);
 this.Font = new System.Drawing.Font("Tahoma", 12F, 
 System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
 this.Margin = new System.Windows.Forms.Padding(5, 4, 5, 4);
 this.Name = "Form1";
 this.Text = "Login";
 this.ResumeLayout(false);
 this.PerformLayout(); 

}
#endregion
private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.TextBox textBox2;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Label label2;
}
}

Don‘t worry about the above automatic generated code; it will be generated automatically, while you design the form in the Design window.
The entire code is generated in a method called InitializeComponent().
Finally, coming to a conclusion; every form contains two files:
Form1.Designer.cs
Contains the code for designing (Automatically generated code by Visual Studio).
Form1.cs
Contains the actual functionality code (Written by the Programmer).

Class Definition Syntax of a Windows Form

//Form1.cs

importing section;
namespace ProjectName
{
 public partial class FormName : Form
  {
   public FormName()
   {
    InitializeComponent();
   }
  }
}

Rules for the Form class definition:

In the importing section, you can import the necessary namespaces that you want.
The namespace name should be same as project name.
A user-defined class with the form name is to be defined.
It should be the sub class of "System.Windows.Forms.Form" class; as it offers some visual design, properties, methods and events for the user-defined form class.
It will be defined as a public class (this is optional). Whenever it is a public class, in future, it can be accessed from other projects also. It should be defined as "partial" class, as its definition is written in the following two files. --> Form1.cs --> Form1.Designer.cs
It should contain a constructor, with a statement called InitializeComponent();, which calls the designer code that is generated in Form1.Designer.cs file.

“Program.cs” file in Windows Forms Applications:

Generally, when you Start the windows application project, automatically the Form1 will be appeared on the screen.
Then don‘t think like directly Form1 will be opened.
In fact, when you click on Start option, the Main() method will be invoked first.
Like Console Applications, Main() method is located in Program.cs file
For reference you open Solution Explorer ―> Program.cs file.
In the Main() method, you can see two important statements.

Application.EnableVisualStyles();

This statement enables the better styles (for sleek appearance) for the entire application, based on the current working theme offered by the O/S.

Application.Run(new Form1());

This statement creates a new Form1 class object and that object will be shown on the screen.

Windows Forms Applications

noreply@blogger.com (fdfsdf) — Mon, 31 Mar 2014 15:59:00 +0000

Next : Development of Form

Windows Forms Applications

C# supports two kinds of User Interfaces.

C.U.I (Character User Interface)

This user interface supports a blank screen, with some characters only.
It is not attractive for the user. That‘s why it is not suitable for the live projects.

G.U.I (Graphical User Interface)

It supports graphical components like windows, icons, mouse pointer, toolbars, status bars, buttons etc.
It is attractive for the user. That‘s why it is suitable for the live projects.
Almost all the software‘s you are using today like Notepad, WordPad, Paint, MS Word, My computer and My documents etc., are the GUI applications.

Windows Forms Application:

It can also be called as Windows Application.
It‘s a collection of windows forms.

Form:

The graphical container, which can contain the graphical controls like labels, textboxes, buttons, list boxes etc., is called as Form. It acts as container for the controls.
It is also called as a window.
It has the visual appearance with a title bar, icon, control box (with minimize button, maximize button and close button)

Creating a “Windows Forms Application” project:

Open Microsoft Visual Studio 2010.
Click on ―> File ―> New ―> Project.
Select the language as Visual C#.
Select the project type as Windows Forms Application.
Enter the name and location of the project.
Click on OK.
Then it will create a windows forms application, along with a form, named Form1.
Then the screen looks like this:

Next : Development of Form

LINQ

noreply@blogger.com (fdfsdf) — Mon, 24 Mar 2014 17:09:00 +0000

LINQ

LINQ stands for "Language Integrated Query".
This concept is introduced in .NET Framework 3.5.
This is a query writing technology.
This is most useful while working large amount of data in the live projects.

INTRODUCTION:

In relational database system, data is organized in the form of tables, on which you can write SQL queries to retrieve the required data according to the requirement in the application.
But you can‘t write a query on the non-database data, which in the form of objects in the application. There, you can write the queries using the new concept called "LINQ".
You can write queries on arrays, objects, databases and XML using LINQ.
Note: Before writing the LINQ queries, you should import the System.Linq namespace..

The following example shows a small demo on LINQ:

PROGRAM FOR LINQ TO ARRAYS

                                                    
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace LINQtoArrayDemo
{
    class Program
     {
       static void Main(string[] args)
       {
         //data source
          int[] numbers = { 2, 12, 10, 5, 15, 4, 62 };
       //ling query
         IEnumerable result = from n in numbers where n <= 10 select n;
       //output
        foreach (var x in result)
        Console.WriteLine(x);
        Console.Read();
      }
    }
}

In the above application, the array contains few numbers. After executing the query, you got only the numbers, which are less than 10. In this manner, you can execute the queries on data sets (after learning ADO.NET) also.

LINQ SYNTAX:

THE ABOVE SYNTAX CONSISTS OF 7 CLAUSES.

from clause
in clause
let clause
where clause
orderby clause
select clause
group by clause
Mandatory clauses:
from clause
in clause
select clause

CLAUSE

Def of Clause: A part of the query.

UNDERSTANDING CLAUSES:

from clause: This is used to specify the iteration variable name. This acts as alias name for the data source.
in clause: This is used to specify the main data source for the query.
let clause (optional): This is used to declare a new identifier with a value, that is to be used during the query execution.
where clause (optional): This is most frequently used optional clause, using which you can specify the condition in the query.
orderby clause (optional): This is used to specify the sorting expression if required.
select clause: This is used to specify the object, which is required in the query results.
group by (optional): This is similar to ―group by‖ clause in SQL. This retrieves grouped data, based on a column.

Note: The result of a LINQ query should be assigned into a IEnumerable type variable. IEnumerable is an interface.

Library: System.Collections.Generic.IEnumerable

PROGRAM FOR LINQ TO OBJECTS

Student.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace LINQtoObjectsDemo
{
   class Student
    {
      //fields
        public int StudentID;
        public string Name;
        public string Course;
        public int Marks;
     //constructor
       public Student(int StudentID, string Name, string Course, int Marks)
        {
          this.StudentID = StudentID;
          this.Name = Name;
          this.Course = Course;
          this.Marks = Marks;
        }
    }
}

Program.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace LINQtoObjectsDemo
{
   class Program
    {
      static void Main(string[] args)
      {
        //data source
          Student[] stu = { new Student(101, "Prakash", "MBA", 765),
          new Student(102, "Pradeep", "MBA", 471),
          new Student(103, "Pushpa", "Msc", 590),
          new Student(104, "Purna", "MCA", 223),
          new Student(105, "Purnima", "MCA", 450)};
       //linq query with where clause
         IEnumerable result1 = from s in stu where s.Course == "MCA" select s;                                                                                          Console.WriteLine("MCA Students:");
         foreach (Student r in result1)
         Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
      //linq query with compound where clause
        IEnumerable result2 = from s in stu where s.Name.EndsWith("a") && s.Marks>=400 &&                                                             s.Marks<=600 select s;
        Console.WriteLine("\nStudents whose name ends with 'a', and marks is >=400 and <=600:");
        foreach (Student r in result2)
        Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);

     //linq query with let and where clauses
       IEnumerable result3 = from s in stu let avg = s.Marks / 10 where avg < 35 select s;
       Console.WriteLine("\nFailed Students:");
       foreach (Student r in result3)
       Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
     //linq query with orderby clause
       IEnumerable result4 = from s in stu orderby s.Marks select s;
       Console.WriteLine("\nStudents (sort on marks):");
       foreach (Student r in result4)
       Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
     //linq query with orderby clause (descending)
       IEnumerable result5 = from s in stu orderby s.Marks descending select s;
       Console.WriteLine("\nStudents (sort on marks - descending):");
       foreach (Student r in result5)
       Console.WriteLine(r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);
    //linq query with group clause
       IEnumerable> result6 = from s in stu group s by s.Course;
       Console.WriteLine("\nStudents with grouping:");
       foreach (IGrouping StuGrp in  result6)
         {
           Console.WriteLine(StuGrp.Key + ":");
           foreach (Student r in StuGrp)
           Console.WriteLine(" " + r.StudentID + ", " + r.Name + ", " + r.Course + ", " + r.Marks);         
         }
        Console.Read();
      }
   }
}

Break Point

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 16:30:00 +0000

EventLog Break Point

Break Point

Bug: : An error.
Debugging: Removing the bugs.

NET offers more features for debugging. To start with the .NET application debugging, you should create the break points.

Definition of Break Point: A break point is a point in the program, where the application execution control pauses until you press F10 key. In the code, that line is highlighted with red color.

Creating a break point: Just click on the left side margin of the required line.

Running the Application with Break Points: Just press F5 key. The application will be executed normally. But whenever the execution control reaches to the break point line, automatically the execution will be paused and the break point line will be highlighted with yellow color. To continue wit h the execution to the next statement, press “F10” key.

Observing the values of variables or objects: While you are executing the application with break points, to know the current value of any variable or object, just place the mouse pointer over it.

Immediate window

The Immediate window resides at bottom side of Visual Studio IDE. It will automatically appear at run time. If not, press Ctrl + Alt + I.

This window is used to know the current values of the required variables, objects or data members, which is not possible to find the value by just placing the mouse pointer over it.

Locals window

It automatically displays all the current local variables along with their values.

To open this window, while running the application, get into the Visual Studio and press Ctrl+D and the L.

EventLog Break Point

Debug

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 16:13:00 +0000

Event Log Break Point

EventLog

EventLog is a service, offered by Microsoft Windows.

It is used to store the exceptions / warnings / any messages permanently, even though the application is closed.

Let us imagine you have done a live project and issue it to the client.

At run time there may be so many exceptions. But after few days, you went to the client location, and want to know what kind of run time errors were coming in your application.

Then no information is available with you.

So, in this case, you require some thing, that stores the exceptions information automatically, for further information, which helps you while you want to debug your application and develop a next version.

That kind of service is EventLog.

To open EventLog and view the current events: Start –> Control Panel –> Administrative Tools –> Event Viewer.

Writing a new entry programmatically:
System.Diagnostics.EventLog.WriteEntry("project name", "message", EventLogEntryType.Error);

Program of Event Log

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Diagnostics; namespace EventLogDemo { class Program { static void Main(string[] args) { try { string filename = "c:\\sample.txt"; StreamReader sr = new StreamReader(filename); string content = sr.ReadToEnd(); Console.WriteLine("The file content is:\n"); Console.WriteLine(content); } catch (Exception ex) { string EventMsg = ex.Message + "\n\n" + ex.StackTrace; EventLog.WriteEntry("My Sample Project 1.0", EventMsg, EventLogEntryType.Error); Console.WriteLine(ex.Message); } finally { Console.WriteLine("Press any key to exit.."); Console.Read(); } } } }

Event Log Break Point

Anonymous Method & Speech Translator

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 16:02:00 +0000

This is used to create a method, without any name.

Syntax:

delegate() { //some code }

PROGRAM OF ANONYMOUS METHOD

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; namespace AnonymousMethodsDemo { class ThreadingDemo { public void Display(string name) { Thread th1 = new Thread(delegate() { while (true) { Console.WriteLine("Welcome to " + name); Thread.Sleep(500); } }); th1.Start(); } } class Program { static void Main(string[] args) { string name; Console.WriteLine("Enter your name:"); name = Console.ReadLine(); ThreadingDemo td = new ThreadingDemo(); td.Display(name); Console.Read(); } } }

SPEECH TRANSLATION

This is to translate the text as speech.

This makes us to listen a voice from the speakers that reads some specified text.

Library: System.Speech.Synthesis.SpeechSynthesizer

This class used to speak the required text through the speakers.

Implementation:

Create the object of SpeechSynthesizer class:
SpeechSynthesizer ss = new SpeechSynthesizer();
Set the volume (1 to 100):
ss.Volume = n;
Set the speed of speaking (-10 to +10):
ss.Rate = n;
Change the voice gender and age:
ss.SelectVoiceByHints(VoiceGender.xxxx, VoiceAge.xxxx);
Speak the text:
ss.SpeakAsync(―message‖);

PROGRAM OF SPEECH TRANSLATOR

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Speech.Synthesis; namespace SpeechTranslationDemo { class Program { static void Main(string[] args) { Console.WriteLine("Enter text to speak:"); string TextToSpeak = Console.ReadLine(); SpeechSynthesizer ss = new SpeechSynthesizer(); ss.Volume = 100; //1 to 100 ss.Rate = -3; // -10 to +10 ss.SelectVoiceByHints(VoiceGender.Female, VoiceAge.Child); ss.SpeakAsync(TextToSpeak); Console.Read(); } } }

Memory Management

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 15:50:00 +0000

Memory Management

Every application requires some amount of memory to run.

That memory will be allocated in the primary memory (RAM).

For every variable, individual memory will be allocated.

The RAM contains two memory locations.
--> Stack

--> Heap

Now, we need to understand, where the application memory is getting allocated in the RAM.

The storage area in the RAM depends on the data type that you are using for declaring the variable in the program.

The data types are two types in C#
--> Value Types

--> Reference Types

Value Type

Def: Whenever a data type is designed based on a structure, it can be called as Value Type.

All the standard data types built based on structures.

You can see the list of data types and respective structures here:

So finally, the following are value types in C#:

Structures

Enumerations

sbyte, byte, short, ushort, int, uint, long, ulong, float, double, decimal, bool, char, decimal, DateTime

Note 1: The value types can‘t be inherited.

Note 2: All the value types (structures and enumerations), are derived from a common base class called System.ValueType.

REFERENCE TYPES:

Def: Whenever a data type is designed based on a class, it can be called as Reference Type.

The following are the reference types in C#:
Classes

Interfaces

String, Object

Reference types support inheritance.

The Value Type variables will be allocated in the Stack.

The Reference Type variables (objects) will be allocated in the Heap.

THE “SYSTEM.OBJECT” CLASS:

This class acts as super class for all other classes (pre-defined / user-defined classes).

So, it can be called as Ultimate base class.

The Object class offers the following methods

PROGRAM OF SYSTEM.OBJECT CLASS

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ObjectClassMethods { class Program { static void Main(string[] args) { int x = 100; int y = 100; Console.WriteLine("x is " + x); Console.WriteLine("y is " + y); Console.WriteLine(); if (x.Equals(y)) Console.WriteLine("x is equal to y"); else Console.WriteLine("x is not equal to y"); Console.WriteLine("\nx is the type of " + x.GetType()); string s = x.ToString(); Console.WriteLine("\nThe integer value after converting into string is: " + s); Console.Read(); } } }

GARBAGE COLLECTOR:

This is one of the components of CLR (Common Language Runtime).

This component is dedicated for de-allocating the un-used memory of the application, automatically.

This uses Mark and Compact algorithm for clearing the un-used memory.

Mark: Markup the un-used objects and push those objects towards up.

Compact: Clear the marked objects memory.

Note: The above functionality is in-built in Garbage collector component. Anyhow, there is a provision for the programmer to command the garbage collector to perform garbage collection at run time, programmatically. Then use the following method from System.GC class. Syn: System.GC.Collect();

Assembly

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 15:22:00 +0000

Assembly Implementation of Share Assemblies Shared Assemblies

Assembly

Def: An assembly is the container of compiled code of .NET applications.

It contains the code in MSIL (Microsoft Intermediate Language) language.

At run time, it will be compiled by CLR‘s JIT compiler into machine language.

The assembly file (with .exe or .dll extension) will be generated in the project folder \bin folder, after compilation.

TYPES OF ASSEMBLIES (BASED ON EXTENSION):

Executable Assemblies / Process Assemblies / Private Assemblies (with .EXE extension)
a. This is generated with

Console Applications

Smart Device Applications

Windows Applications

b. These files are ready for execution. You can execute those by simply double clicking.

Limitation: The code in this assembly is not accessible from other projects.

Library Assemblies / Re-usable Assemblies / Shared Assemblies (with .DLL extension)
i. This is generated with

Class Library

Windows Forms Control Library

ii. These are non-executable files.

Advantage: The code is this assembly is accessible from other projects.

Overview of “Class Library” Project

A class library project is meant for the development of Shared Assemblies.

The shared assemblies are re-usable in other applications also.

That means the class library‘s code is re-usable in other applications, whenever required.

Class library project contains only user-defined classes.

Whenever the class library project is compiled, a library assembly file (with .DLLextension) will be generated in the ―bin\Debug folder.

The class library project can‘t be executed directly unlike console applications, windows applications etc.

Global Assembly Cache (GAC):

All the shared assemblies should be saved in the GAC. GAC offers the following advantages.

Unique identification of the shared assemblies.

Avoids the DLL hell (replacement of an assembly related to one application, by another application).

Faster accessibility.

To view the currently installed assemblies in the GAC, open the following folder C:\windows\assembly The above folder is able to contain multiple dll files with same name, with different versions.

STRONG NAME KEYS (SNK):

The strong name key is a file, which acts as a unique identifier, for the shared assemblies, stored in the GAC. In other words, GAC recogniz es the assembly with this strong name only.

Assembly Implementation of Share Assemblies Shared Assemblies

Implementation of Shared Assemblies

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 15:21:00 +0000

Assembly Implementation of Shared Assemblies Shared Assemblies

Implementation of Shared Assemblies

Create a Class Library Project.

Create a new Class Library project.

Write the required code in the project.

Create a strong name key.

Right click on the project in the Solution Explorer and choose Properties.

In the project properties, select the check box Sign the assembly.

In the Choose a strong name key file‖ drop down, select <New> option.

In the Create strong name key‖ dialog box, enter the name of the strong name key file.

If password security is not required, uncheck the Protect my key file with a password checkbox.

Click on OK.

Customize the “Assembly Information” (AssemblyInfo.cs).

This is optional step.

To change the additional details of the assembly like displayed name, version, company, copy right, description etc., open “AssemblyInfo.cs” file from the Properties folder in the Solution Explorer.

Generate the DLL File.

Build the class library project.

Then the .dll‖ file will be generated in the bin\debug folder of your class library project.

Write the assembly into GAC (Global Assembly Cache).

Open the following folder.
C:\Windows\Assembly
Drag and drop the ―.DLL file‖ from ―bin\Debug‖ folder into the
c:\windows\assembly folder.
After dragging, the name of your shared assembly will appear in the existing list.

Now, the shared assembly is ready. The rest of your work involved with the usage of the shared assembly.

Invoke the Shared Assembly.

Create the executable project (Console application / windows application).

Click on Project – Add Reference.

Click on Browse tab.

Open the class library project‘s bin\Debug folder.

Select the dll file and click on OK.

Then the reference of the selected shared assembly will be added to the current project.

Then you can construct objects for the required class in the class library and perform required activities on that.

Assembly Implementation of Shared Assemblies Shared Assemblies

Shared Assemblies

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 15:21:00 +0000

Assembly Implementation of Shared Assemblies Shared Assemblies

Shared Assembly

CREATE A CLASS LIBRARY PROJECT.

Open Visual Studio 2008.

Click on ― > File‖ ―> New ―> Project.

Select the language as ―> Visual C# and project template as ―> Class Library.

Enter the name as ―> SharedAssemblyLibrary.

Click on OK. It creates a new class library project. Initially it contains a new class called class1.

In the solution explorer, rename the class1.cs as "MyLibraryClass.cs”.

Then type the following code.

PROGRAM FOR CLASS LIBRARY PROJECT

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace SharedAssemblyLibrary { public class MyLibraryClass { public bool IsValidLogin(string Username, string Password)\ { if (Username == "system" && Password == "manager") return true; else return false; } } }

CREATE A STRONG NAME KEY.

Right click on the project in the Solution Explorer and choose Properties.

In the project properties, select the check box Sign the assembly

In the Choose a strong name key file drop down, select option.

In the Create strong name key‖ dialog box, enter the name of the strong name key file as “MyKeyFile”.

Uncheck the ―Protect my key file with a password‖ checkbox.

Click on OK.

CUSTOMIZE THE “ASSEMBLY INFORMATION” (ASSEMBLYINFO.CS).

Change the assembly version as “1.5.0.0”.

GENERATE THE DLL FILE.

Build the class library project by clicking on ―Build‖ menu – ―Build Solution‖.

WRITE THE ASSEMBLY INTO GAC (GLOBAL ASSEMBLY CACHE).

Open the following folder

C:\Windows\Assembly

Drag and drop the “SharedAssemblyLibrary.DLL‖ file from ―bin\Debug‖ folder into the c:\windows\assembly folder.

INVOKE THE SHARED ASSEMBLY.

Create a new Console Application. Name: SharedAssemblyDemo

Click on Project ― Add Reference.

Click on Browse tab

From the class library project‘s bin\Debug‖ folder, select the “SharedAssemblyLibrary.dll file and click on OK. Then the .dll file reference will be added

PROGRAM FOR SHARED ASSEMBLIES

using System; using System.Collections.Generic; using System.Linq; using System.Text; using SharedAssemblyLibrary; namespace SharedAssemblyDemo { class Program { static void Main(string[] args) { MyLibraryClass mlc = new MyLibraryClass(); string Username, Password; Console.Write("Enter Username: "); Username = Console.ReadLine(); Console.Write("Enter Password: "); Password = Console.ReadLine(); bool result = mlc.IsValidLogin(Username, Password); if (result == true) Console.WriteLine("\nLogin successful!"); else Console.WriteLine("\nInvalid Username / Password!"); Console.Read(); } } }

Assembly Implementation of Shared Assemblies Shared Assemblies

Multi Threading & Thread State

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 14:31:00 +0000

Multi Threading Thread State

Multi Threading

Multi Threading is one of the rich features of .NET applications.

Using this feature, the user is able to create multi-threaded applications.

This concept is introduced in VC++. This is also supported by Java.

Definition of Multi Threading: The ability of an application that maintains multiple threads at run time.

Definition of Thread: The thread is a sub process (part of the process). That means it has some code to execute.

Advantage of Multi-Threading: Using multi threading‖, you can break a complex task in a single application into multiple threads that execute independently and simultaneously.

In other words, multi threading is the sub form of multi tasking.

Before starting with the implementation of Multi Threading, you should recollect the concept of Multi-Tasking.

MULTI TASKING:

Def: Ability of the OS, that is able to perform more than one task, at-a-time (simultaneously) is called as Multi-Tasking.

As a part of this, OS allocates the CPU clock (CPU capacity) for each task.

Note: Just like multi-tasking, OS allocates the CPU clock for each thread.

THREADING ARCHITECTURE

Implementation of Multi Threading:

.NET Framework offers a namespace called “System.Threading” for implementation of multi threading.

Library: System.Threading.Thread
This class object represents a thread.

Import the API:
using System.Threading;
Create the Thread Object:
Thread th = new Thread(method name);
Start the Thread:
th.Start()

Program for Multi-Threading

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; namespace SimpleThreadingDemo { class ThreadingDemo { private void FirstMethod() { for (int i = 1; i <= 300; i++) Console.Write("i=" + i + " "); } private void SecondMethod() { for (int j = 1; j <= 300; j++) Console.Write("j=" + j + " "); } public void Display() { Thread th1 = new Thread(FirstMethod); Thread th2 = new Thread(SecondMethod); th1.Start(); th2.Start(); } } class Program { static void Main(string[] args) { ThreadingDemo td = new ThreadingDemo(); td.Display(); Console.Read(); } } }

Multi Threading Thread State

/div>

Thread State

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 14:09:00 +0000

Multi Threading Thread State

Thread State

The thread state specifies the current status of the thread. Sometimes, the thread automatically switches from one state to another state automatically; at some other times, you can switch its state by using the methods offered by Thread class.

The following diagram called Thread Life Cycle describes the different states of a thread.

Ready: This is the initial state. The thread object is created.

Running: The thread is currently being executed.

Sleeping: The thread is temporarily paused. .NET framework offers automatic switching between Running and Sleeping states, when other threads are executed.

Suspended: The thread is temporarily suspended (paused). It will be continued, when you call Resume() method.

Dead: The thread was closed; it can‘t be restarted or continued.

Thread class methods:

thobj.Start() : This method starts-up the thread execution.

Thread.Sleep(mille sec) : This method puts the thread under Sleeping state, up to a certain no. of mille seconds. When the given no. of mille seconds are completed, automatically the thread execution will be continued.

thobj.Suspend() : This is similar to Sleep() method, but here, no time limit will be given. That means whenever the Suspend() method is called, the thread will be put under Suspended state, until the Resume() method is called.

thobj.Resume() : This is to continue the thread execution that is under Suspended state. This method won‘t work if the thread is not under Suspended state.

thobj.Abort() : This is close the thread execution completely, at any time. Once, if the Abort() method is called, the thread can‘t be started or resumed. This is the end of every thread life cycle

Program of Thread State

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading; namespace ThreadLifeCycleDemo { class ThreadingDemo { private void FirstMethod() { for (int i = 1; i <= 50; i++) { Console.Write("i=" + i + " "); Thread.Sleep(1000); } } private void SecondMethod() { for (int j = 1; j <= 50; j++) { Console.Write("j=" + j + " "); Thread.Sleep(1000); if (j == 20) th1.Suspend(); else if (j == 30) th1.Resume(); } } Thread th1, th2; public void Display() { th1 = new Thread(FirstMethod); th2 = new Thread(SecondMethod); th1.Start(); th2.Start(); } } class Program { static void Main(string[] args) { ThreadingDemo td = new ThreadingDemo(); td.Display(); Console.Read(); } } }

Multi Threading Thread State

Exception Class

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 13:45:00 +0000

Exception Handling Exception Class

Exception Class

Already you know that C# recognizes the exception as an object.

To declare the exception object, we have used a class called System.Exception, in the previous examples.

The Exception class recognizes any type of exceptions. In order to catch the particular type of error, C# provides other exceptional classes. Some of them are given here.

Exception Class Description

System.OverflowException Occurs when a large value is assigned to a variable, which is not fit in that variable.

System.FormatException / System.InvalidCastException Occurs when the casting is failed from one data type of another data type.

System.DivideByZeroException Occurs when any number is divided by 0.

System.IndexOutOfRangeException Occurs when an index is accessed in out of range.

System.InsufficientMemoryException Occurs when there is no sufficient memory in RAM for the execution of the application.

System.IO.FileNotFoundException Occurs when a non-existing file is accessed.

System.IO.DirectoryNotFoundException Occurs when a non-existing directory is accessed.

System.IO.FileLoadException Occurs when any error occurred during the opening of any file.

System.IO.IOException Occurs when any error occurred during file read or writing.

System.Threading.ThreadInterruptedException Occurs when any error occurred during the execution of the thread.

System.Threading.ThreadStartException Occurs when any error occurred while starting the thread.

System.InvalidOperationException Occurs when any error occurred while opening the database connection.

System.Data.OleDb.OleDbException Occurs when any error occurred while performing query or non-query transactions on OleDb databases.

System.Data.SqlClient.SqlException Occurs when any error occurred while performing query or non-query transactions on SqlServer database.

System.EntryPointNotFoundException Occurs when you try to run the application, without defining any entry point (main() method).

System.InvalidTimeZoneException Occurs when the system has an invalid time zone setting the date & time settings.

PROGRAM OF EXCEPTION CLASS

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ExceptionDemo3 { class Program { static void Main(string[] args) { try { int n1, n2, n3; Console.WriteLine("Enter first value:"); n1 = Convert.ToInt32(Console.ReadLine()); Console.WriteLine("Enter second value:"); n2 = Convert.ToInt32(Console.ReadLine()); n3 = n1 / n2; Console.WriteLine("Result is: " + n3); } catch (DivideByZeroException ex) { Console.WriteLine("Can't divide the number with zero."); } Console.Read(); } } }

Note: If you want to handle more than one type of exception for the same try block, then you need to write multiple catch blocks

PROGRAM FOR MULTIPLE CATCH BLOCK

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ExceptionDemo4 { class Program { static void Main(string[] args) { try { int n1, n2, n3; Console.WriteLine("Enter first value:"); n1 = Convert.ToInt32(Console.ReadLine()); Console.WriteLine("Enter second value:"); n2 = Convert.ToInt32(Console.ReadLine()); n3 = n1 / n2; Console.WriteLine("Result is: " + n3); } catch (DivideByZeroException ex) { Console.WriteLine("This is divide by zero exception."); } catch (OverflowException ex) { Console.WriteLine("This is overflow excpetion."); } catch (FormatException ex) { Console.WriteLine("This is invalid cast exception."); } Console.Read(); } } }

Exception Handling Exception Class

Exception Handling & Exception Class

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 13:33:00 +0000

Exception Handling Exception Class

Exception Handling

This is one of the major features of OOP languages like C++, VC++, VB.NET, C#.NET, Java etc.

Def: The process of handling the run time exceptions" is called as "Exception handling".

Note: Exception = Run time error

Types of Errors:

Compile Time Errors: The errors occurred after compiling the program, are called as compile time errors.

Run Time Errors: The errors occurred during the execution of the program, are called as run time errors.

Overview of Exception Handling:

The exception may occur at run time, based on the mistake of the user / programmer / system problem also.

When exception is raised, automatically it leads to "abnormal application termination".

The cause of the exception may be anything; the project developer should take care about the exceptions.

As a part of this exception handling, the programmer has to display "particular error message" to the user.

Purpose of Exception Handling: To avoid "abnormal application termination", even though exception occurs.

Types of Application Termination:

Normal Application Termination: Whenever the program execution controls executes all the statements in the program and reaches to end of the code, the application will be terminated automatically. It can be called as Normal Application Termination.

Abnormal Application Termination: Whenever an exception occurred at run time, the application will be terminated automatically. It can be called as Abnormal Application Termination.If the application was terminated abnormally, if will be most inconvenience for the user. So being a programmer, you are responsible to avoid that kind of abnormal application termination, even though exception is occurred at run time

Program of Exception Demo

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ExceptionDemo1 { class Program { static void Main(string[] args) { string[] Cities = { "Vijayawada", "New Delhi", "Banglore", "Hyderabad" }; Console.WriteLine(Cities[3]); Console.WriteLine(Cities[4]); Console.Read(); } } }

In the above code, the highlighted line contains an error, because it is trying to access an array element which is in out of range of the array. So, it leads to abnormal application termination at run time .

/*Syntax Of Exception ------------------------------*/ try { } Catch (Exception ex) { } Finally { }

try block:

The try block contains the actual code, which is to be executed.

After every try block, there should catch block without fail.

The system tries to execute the code in the try block.

During the execution, if any exception occurs, then the execution control automatically goes to catch block.

At the same time, the try block throws the exception to the catch block in the form of an object. That object is called as exception object.

catch block:

This is also known as error handler.

This is followed by the try block.

The catch block will be executed if any exception is occurred during the execution of try block.

The catch block contains necessary code which displays an error message to the user.

This receives the exception, thrown by the try block, in the form of an object. In the following syntax, ex is the Exception object. The Exception is the class for the exception object.

Library: System.Exception

finally block:

This block will be executed automatically and compulsorily, after executing try block / catch block.

That means even though exception is raised or not raised, the finally block will be executed without fail.

This is optional block. You can write the exception handling syntax only with try and catch blocks, without finally block.

PROGRAM OF EXCEPTION HANDLIGN

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ExceptionDemo2 { class Program { static void Main(string[] args) { try { string[] Cities = { "Vijayawada", "New Delhi", "Banglore", "Hyderabad" }; Console.WriteLine(Cities[3]); Console.WriteLine(Cities[4]); } catch (Exception ex) { Console.WriteLine("Error occurred."); } finally { Console.WriteLine("This is 'finally' block."); Console.Read(); } } } }

Types of Catch Block Messages:

Already we have discussed that the catch block generates an error message, when an exception occurs. That error message can be of two types.

User Defined Message

System Defined Message

User Defined Message: Your own message can be written.
Error Occurred.

Operation is not successful. etc.

System Defined Message: The system provides the description of the error, so that you can print that on the output directly. To access the system defined message, you can use the exception object as follows:
Syn:ex.Message

Example:

Exception Handling Exception Class

Print Document Class

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 12:46:00 +0000

Collection Collection Initializer Printi Document Class

Print Document Class

.NET supports to print any type of documents through the printer.
Library: System.Drawing.Printing.PrintDocument
This class object represents a document (any type of file), that is ready to print.
Note: By default, System.Drawing assembly will not be linked with the Console applications.
That‘s why you need to add a reference to that as follows:

Click on ―> Project menu ―> Add Reference.

Select ―> System.Drawing assembly.

Click on OK. Then the System.Drawing assembly will be linked with the current project and it will be displayed in References folder in the Solution Explorer.

Implementation:

Import the namespace: using System.Drawing.Printing;

Construct the object:
PrintDocument obj = new PrintDocument();
Assign the document name, that is to be printed:
obj.DocumentName = file path to be printed;
Start Printing:
obj.Print();

PROGRAM FOR PRINT CLASS

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Drawing.Printing; namespace PrintingDemo { class Program { static void Main(string[] args) { PrintDocument doc = new PrintDocument(); doc.DocumentName = "c:\\SampleDocument.doc"; doc.Print(); Console.WriteLine("Printing started..."); Console.Read(); } } }

Collection Collection Initializer Printi Document Class

Collections

noreply@blogger.com (fdfsdf) — Sun, 09 Mar 2014 12:44:00 +0000

Collection Collection Inititalizer Print Document Class

Collection

The concept of collections is basically developed from Arrays.

Already you know that, arrays are multiple value containers of fixed type.

In order to hold different types of values on the same array, you require collections.

Another advantage of collections is those are dynamic sizable. In other words, the array is of fixed size and the collection is of dynamic size.

Finally, if you don‘t know how many values are to be stored in the array at the time of its declaration, you require to use collections; (or) if you want to store different type of values in the same array, at that case also, you require to use collections.

.NET offers some pre-defined classes for maintenance of collections.

Collection Classes:

List:

Contains n no. of values of same type. It‘s a generic class.

This is member of ―System.Collections.Generic” namespace.

ArrayList:

Contains n no. of values of different types.

This is member of System.Collections namespace

Implementation of “List” class:

Import namespace:

using System.Collections.Generic;

Create instance:

List<data type> obj = new List<data type>();

Add values:

obj.Add(value);

Get the currently existing no. of values in the collection:

obj.Count

Get the individual element in the collection:

Implementation of “ArrayList” class:

Import namespace:

using System.Collections;

Create instance:

ArrayList obj = new ArayList();

Add values:

obj.Add(value);

Get the currently existing no. of values in the collection:

obj.Count

Get the individual element in the collection:

obj[index];

Program of List Class

using System.Collections.Generic; namespace ListClass { class Program { static void Main(string[] args) { List MyMessages = new List(); MyMessages.Add("Good Morning"); MyMessages.Add("Good Afternoon"); MyMessages.Add("Good Evening"); MyMessages.Add("Good Night"); //MyMessages.Add(10); //error Console.WriteLine(MyMessages.Count + " messages found.\n"); foreach (string s in MyMessages) { Console.WriteLine(s); } Console.Read(); } } }

PROGRAM OF ARRAYLIST CLASS

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Collections; namespace ArrayListClass { class Program { static void Main(string[] args) { ArrayList al = new ArrayList(); al.Add("Hai"); al.Add("How r u"); al.Add(1000); al.Add(true); al.Add(DateTime.Now); Console.WriteLine(al.Count + " values found.\n"); for (int i = 0; i < al.Count; i++) Console.WriteLine(al[i]); Console.Read(); } } }

Collection Collection Inititalizer Print Document Class

Exception Class	Description
System.OverflowException	Occurs when a large value is assigned to a variable, which is not fit in that variable.
System.FormatException / System.InvalidCastException	Occurs when the casting is failed from one data type of another data type.
System.DivideByZeroException	Occurs when any number is divided by 0.
System.IndexOutOfRangeException	Occurs when an index is accessed in out of range.
System.InsufficientMemoryException	Occurs when there is no sufficient memory in RAM for the execution of the application.
System.IO.FileNotFoundException	Occurs when a non-existing file is accessed.
System.IO.DirectoryNotFoundException	Occurs when a non-existing directory is accessed.
System.IO.FileLoadException	Occurs when any error occurred during the opening of any file.
System.IO.IOException	Occurs when any error occurred during file read or writing.
System.Threading.ThreadInterruptedException	Occurs when any error occurred during the execution of the thread.
System.Threading.ThreadStartException	Occurs when any error occurred while starting the thread.
System.InvalidOperationException	Occurs when any error occurred while opening the database connection.
System.Data.OleDb.OleDbException	Occurs when any error occurred while performing query or non-query transactions on OleDb databases.
System.Data.SqlClient.SqlException	Occurs when any error occurred while performing query or non-query transactions on SqlServer database.
System.EntryPointNotFoundException	Occurs when you try to run the application, without defining any entry point (main() method).
System.InvalidTimeZoneException	Occurs when the system has an invalid time zone setting the date & time settings.