Lets start with sharing

Converting List to DataTable in C#

2019-11-23T18:54:00.001-08:00

public static DataTable ConvertToDataTable<T>(IList<T> data)
{
PropertyDescriptorCollection properties =
TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
foreach (PropertyDescriptor prop in properties)
table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
foreach (T item in data)
{
DataRow row = table.NewRow();
foreach (PropertyDescriptor prop in properties)
row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
table.Rows.Add(row);
}
return table;

}

Introduction to Entity Framework

2019-04-24T04:00:00.000-07:00

Entity Framework is an object-relational mapper (O/RM) that enables .NET developers to work with a database using .NET objects. It eliminates the need for most of the data-access code that developers usually need to write.

It enables developers to work with data using objects of domain specific classes without focusing on the underlying database tables and columns where this data is stored.
It eliminates the ADO.NET code that we write to connect to Database,Execute Query and read data from DataSet and convert to .net objects and vice versa.

It Reduces the pain of developers and provides higher level of abstraction for faster development of .net applications.

Adding User To Role Using Identity

2019-04-21T20:34:00.001-07:00

First Create a viewmodel

public class ApplicationUserRoleViewModel
{
public string UserId { get; set; }

public string RoleId { get; set; }

}

Create an Empty Controller with name UserAndRolesConroller and add the following actions

public async Task<ActionResult> AddUserToRole()
{
ApplicationUserRoleViewModel vm = new ApplicationUserRoleViewModel();
var Users = await dbCon.Users.ToListAsync();
var roles = await dbCon.Roles.ToListAsync();
ViewBag.UserId = new SelectList(Users, "Id", "UserName");
ViewBag.RoleId = new SelectList(roles, "Id", "Name");
return View(vm);
}

[HttpPost]
public async Task<ActionResult> AddUserToRole(ApplicationUserRoleViewModel model)
{
var role = dbCon.Roles.Find(model.RoleId);
if (role != null)
{
await UserManager.AddToRoleAsync(model.UserId, role.Name);
}
return RedirectToAction("AddUserToRole");

}

Create a view by clicking in the action and giving the same name

@model WebApplication1.Models.ApplicationUserRoleViewModel

ViewBag.Title = "AddUserToRole";

}

<h2>AddUserToRole</h2>

@using (Html.BeginForm())

{

@Html.AntiForgeryToken()

<h4>Attendance</h4>

<hr />

@Html.Label("UserId", htmlAttributes: new { @class = "control-label col-md-2" })

@Html.DropDownListFor(model => model.UserId, null, htmlAttributes: new { @class = "form-control" })

</div>

@Html.Label("RoleId", htmlAttributes: new { @class = "control-label col-md-2" })

@Html.DropDownListFor(model => model.RoleId, null, htmlAttributes: new { @class = "form-control" })

</div>

</div>

}

Converting DataTable to List

2019-04-20T20:29:00.001-07:00

Calling from Controller

public ActionResult Index()
{
//join use
//change view model.
String sql = "SELECT * FROM faculties ";
db.List(sql);
var dt = db.List(sql);
var model = new Faculty().List(dt);
return View(model);
}

Add a method to class

List<Faculty> list = new List<Faculty>();

public List<Faculty> List(DataTable dt)

{

for (int i = 0; i < dt.Rows.Count; i++)

{

Faculty fac = new Faculty();

fac.FacultyId = Convert.ToInt32(dt.Rows[i]["FacultyId"]);

fac.Name = dt.Rows[i]["Name"].ToString();

fac.Description = dt.Rows[i]["Description"].ToString();

list.Add(fac);

}

return list;

}

Using SqlDataAdapter to fill DataTable in c#

2019-04-20T20:25:00.003-07:00

public DataTable List(string sql)
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString);
SqlCommand cmd = new SqlCommand(sql, con);

DataTable dt = new DataTable();
SqlDataAdapter da = new SqlDataAdapter(cmd);
try
{
con.Open();
da.Fill(dt);
}
finally
{
con.Close();
}
return dt;
}

Connection String in ASP.NET With SQL Server

2019-03-23T08:35:00.002-07:00

Connection string can be placed in web.config file found in root directory of the application from .NET 3.5 onward.
connection string can be specified with an xml tag <connectionStrings> inside <configuration> section of web.config file.

<connectionStrings> <add name="myConnectionString"
connectionString="Data Source=databaseServerName;
database=database-name;
uid=sqlUserName;password=sqlPassword;
Integrated Security=True|false|SSPI (any one options) ;"
providerName="System.Data.SqlClientSystem.Data.SqlClient" />
</connectionStrings>

We can use local database server of SQL Server by using
Data Source=(LocalDb)\MSSQLLocalDB
we can attach a local database file to the app_data directory by using the property
AttachDBFilename=|DataDirectory|\appDatabaseName.mdf in the connection string

Connection String can be accessed in a class file by using System.Configuration namespace
and using the ConfigurationManager class.

SqlConnection con =new SqlConnection(ConfigurationManager.ConnectionStrings["connectionStringName"].ConnectionString);

Knowing Nuget and installing a Package

2019-03-16T10:02:00.003-07:00

For .NET Microsoft-supported mechanism for sharing code is NuGet, which defines how packages for .NET are created, hosted, and consumed, and provides the tools for each of those roles.
It has been an essential tool for through which developers can create, share, and consume useful code. Often such code is bundled into "packages" that contain compiled code (as DLLs) along with other content needed in the projects that consume these packages.

How to add Nuget Package to an application

Right click Refrences -> Manage Nuget Packages2. Type Nuget Package Name you need for the application here we add Entity Framework

3. After the search result is shown click install and accept the agreement asked

After this the package is installed and you can use the functionalities that are provided by the package.

Models In Asp.net MVC

2019-03-16T09:37:00.000-07:00

What is a Model?
Model is a class that represents domain specific data and business logic in a dot net application.

Adding A Model
Right click the Models folder in the solution explorer->Add -> Class

After that Select Visual C#-> Class and provide a suitable name for your model class

Sample Model Class

In Model validation logic can be added using Attributes in C# . Some validation attributes like StringLength,RegularExpression are used in the model.

Getting Started With ASP.NET MVC First Application

2019-03-16T09:03:00.002-07:00

Requirements: Visual Studio (i am using VS 2017 for demo)

Open up the visual studio and Click File -> New ->Project
Click Visual C# -> Asp.Net Web Application (.NET Framework) In the Name i.e Project Name and Solution give the name as required here I have given Name: WebApp Solution Name: StudentInformation
Select MVC and then click OK
The application will open with the following view
Run the application from the menu bar or can press F5 or CTRL+F5

The first ASP.NET MVC Application is up and running in your web browser. It opens the applications home page and opens in the web browser with localhost:port . Visual studio assigns the random port number and hence the port number you see differs.

Introduction to ASP.NET MVC

2019-03-16T08:01:00.001-07:00

What Is Asp.Net MVC ?
Asp.net MVC is a framework introduced by microsoft in 2008 for building web application.
Asp.net MVC is an architectural pattern built on top of ASP.Net Framework for development of
application based on three main logical components.
Asp.net MVC is lightweight and testable framework and can be used to develop highly scalable and extensible enterprise level applications.
Three main components of MVC
1. Model
Model is a data specific logic that the application works with.It generally represents the data that is transferred between storage layer and application and between view and controller.
In general Model is a class that contains properties specific to the application domain and transfer data between different components.
2.View
View is an user interface that can use model to populate data to the users. They are results of the request made by an user to the application and is returned from controller.
3. Controller
Controller is a component that handles all the incoming request of the application and provides response to the request.
It generally is an interface that interacts between View and Model and hence renders output for the requests.

Introduction to Microsoft SQL Server

2019-02-24T08:26:00.003-08:00

Microsoft SQL Server is a Relational Database Management System(RDBMS) developed by Microsoft. It is one of the most popular RDBMS. SQL server has evolved from sql 1.0 in 1989 to the latest release of SQL Server 2019 (preview) to become one of the best enterprise level database server's.
SQL server is released with different editions.

Express: Free to use entry level database which can use 1 core cpu, 1 GB ram and have maximum size of 10GB.
Compact : Free embedded database for mobile app development and can have maximum size of 4GB.
Enterprise : Full featured top end edition.
Standard : Have less features than enterprise.
WorkGroup: suitable for a company to use among the group.
Developer: Same features like enterprise but is licensed to one user only.
Web: Specially targeted for web application

There are some other editions like Datacenter, Enterprise evaluation and Business Intelligence.

These all editions are not available on all version of SQL Server.

Now: For learning purpose i will recommend you to download express edition

you can download 2017 express edition by visiting this link click here

RDBMS

RDBMS is a database management system that is based on the relational model introduced by Edgar F. Codd .It has been a widely used option for storage of information in a database.It is the basis for SQL, and most of the modern database systems like MS SQL,IBM.

SSMS(Sql Serever Management Studio)It is a software application that is used to configure, manage, and administer all components within the SQL Server.

SSMS was a part of the SQL server during installation in older version of SQL Server( before Sql Server 2014) but later SSMS is a separate installation.Download SSMS 2017 by visiting this link click here

Update column with data from another table in SQL

2019-02-02T23:32:00.001-08:00

At different point of time we come up with a situation

where we need to update a column in a table from another

 table based on some condition.

So a Basic Syntax for update is:

UPDATE table
SET column1 = expression1,
    column2 = expression2,
    ...
[WHERE conditions];

For us to update based on another table we will be using the

same syntax for update  applying join with another table from

 where we need the data.

UPDATE t1
  SET t1.column_to_update= t2.column_from_update
  FROM Table1 t1
  INNER JOIN Table2 AS t2
  ON t1.common_column= t2.common_column

Extract Week Start Date and End Date from a given date in c#

2019-01-28T01:52:00.000-08:00

Configure DNS to use an external mail server in Windows Server

2019-01-28T00:20:00.002-08:00

External mail server can be used in the hosting server by configuring Mail Exchange (MX) Record.

The Domain Name System(DNS) has several types of resource records that full fill the name to ip address translation(Directly or indirectly). One of the widely used record is MX Record.

An MX record should return the fully qualified domain name of an email server and its preference value .
MX Record can be configured by following the step below.

1. Open DNS Manager
2. Add A Record for your mail
(eg: mail.domain.com with the ip address of another server)

3. Add MX Record and set FQDN to the name assigned in A Record
(i.e mail.domain.com)
Preference number can have any value between 0 to 65535 and lower number sets for higher priority.

After completing this step, The mail server is pointed to the ip addres provided in the A record for the specific domain.

SqlException: Login failed for user 'IIS APPPOOL\

2019-01-26T01:02:00.001-08:00

This issue is related with the permission for application pool to connect with the sql.
We can create login user with the name as specified in the exception IIS APPPOOL\<name>
and grant permission to the database.
We can create new login user by opening the SSMS(Sql server management studio) navigate to Security>Login
Then Add the user by right clicking Login and selecting new login
While creating user Navigate to UserMapping and tick the database for the specific user.

This process will create the new user and gran permission to the user.

Another Work Around
Yet another simple way will be to change the application pool Identity property To LocalSystem by navigating to the application pool and then advance setting.

Bubble Sort in C-Sharp

2019-01-21T09:28:00.001-08:00

Bubble Sort is a simple sorting algorithms that iterates through a list and compares adjacent item and swaps them in the order if they are in the wrong order. The iteration is completed after the items bubble to there specific position and the list is sorted ascending or descending.
Bubble sort is simple but too slow and impractical in most of the cases.

Figure :

Algorithm:

 for all elements in Array
      if Array[i] > Array[i+1]
         swap(Array[i], Array[i+1])
      end if
   end for
    return Array

CODE :

Reading and Writing to a file text file in C#

2019-01-14T09:21:00.000-08:00

Lets start by taking the below code as an example:

private void WriteToAFile(){

string data = "hi ! what's up";

string path = "data.txt";

if (!File.Exists(path))

{

File.Create(path);

}

using (StreamWriter writer = new StreamWriter(path, append: true))

{

writer.WriteLine(data);

}

Writing to a text file can be achieved by using StreamWriter class . To use this class we need to use System.IO namespace.

if we are writing to a file then exception might occur if the file doesn't exists. So firstly we need to check if the File Exists. If it doesn't exist we can create a file in the path specified.

Here in example I haven't provided the fully qualified path like

"C:\Users\Mypc\project\Sample" absolute path

but rather used relative path by providing only the file name.

The file will be created inside the bin folder either in debug or release depending on how you run.

Creating object of StreamWriter by passing path and true as parameter.

Append mode opens file and moves pointer to the end of file, so the next thing you write will be appended else the existing data will be overwritten.

WriteLine method writes stream to the file with line terminator.

Similar Write method can be used to write string to the file.

there are several overloading methods to these stated methods.

Reading from a text file

Reading can be achieved by using StreamReader class.

below is the code example to read from an existing text file:

using (StreamReader sr = new StreamReader(path))
{
while ((line = sr.ReadLine()) != null)
{
Console.WriteLine(line);
}
}

Classes and Objects In C#

2019-01-13T08:40:00.000-08:00

Class is a collection of fields, properties and methods. It depicts real life entities and is a fundamental concept in Object Oriented Programming.

A class is a user-defined blueprint from which objects are created . A class is a user defined data type of reference type.

Lets take a example of a Car . It has different attributes like color,maximum speed,no of gears on with a built in audio player and so on.

public class Car

{

private string _color; //a variable and a field with data type string

// a variable and a property

public string Color

{

get

{

return _color;

}

set

{

_color= value;

}
public void PlayAudio()
{
//implementation logic
}

}

Declaration Of Class:
<access specifier><keyword:class> <class name: Car>
public class car

if access identifier is not explicitly mentioned a class has internal access identifier as default while methods and properties have private access identifier.

Fields : field is private to the class and stores the actual data.

Properties : Properties are exposed contract which uses the underlying fields.
Properties are also called accessors as they offer a way to get and set a field in the class.
Properties can be read-only,write-only or both by declaring get{},set{} or both.

Object :
Object is an instance of a class which is created at run time. It is a memory allocation according to the class of which it is an instance of . It is used to access properties and methods in a class.

Initializing an object
An object is initialized by using the keyword new.

Car c=new Car();
here c is an object of type car.
if we split the above initialization in two lines
Car c ; // it is a declaration which states that c is a variable of type class c;
c=new Car();// now c is an object of class Car

and we can access the properties and methods of the class
c.Color=red; //assigning value to the property of the object
string color=c.Color; //getting the value of the property from the object
c.PlayAudio(); //invoking method

Installing Windows Service

2019-01-10T02:19:00.001-08:00

What is a windows Service ?
Windows service is a long running process that runs as a background process in windows OS.
We create windows service when we need to perform tasks without the user interaction. Like regular application windows services lacks UI for user interaction.

We can install windows service by navigating to installutil.exe file that resides in Microsoft.Net Folder inside Windows folder.
For for .net version 4
the file path is C:\Windows\Microsoft.NET\Framework\v4.0.30319
we can install the service by running the following command in CommandLine opening it as an Administrator.

"C:\Windows\Microsoft.NET\Framework\v4.0.30319\installutil.exe" "E:\servicename.exe"

See the following command run  for installing the merotrackerlistener in the system.

After running the command windows service is installed in the system.

6 Points to Learn Programming for Beginner's

2017-02-17T06:45:00.000-08:00

Learning programming isn't that hard neither that easy,But will be simplified once you are in a right direction and know how to.There are lot of things that you can do to making the learning easier.

Don't Move too Fast

    Learning is not a race, so keep calm and get it right before moving on, rather then quickly jumping for next. Thinking you know it all but you rarely did will be hindrance as you miss out the things and not have good good grasp of the fundamentals.
Take it as a continuous process and don't stop try maintaining the pace till you have mastered the topic

2. Understand the Example Code
Reading codes doesn't help you to write a program.What matters is understanding the code, so try to understand the code and always keep in mind start from the simple code don't flow on the words and go for complex code. Once you understand simple codes you will eventually grow yourself to understand the complexity.

3.Execute The Code
    Don't just be happy thinking that you have understood the code.You felt it and what you have felt might not really be. So type the code in the editor or IDE and run it,But wait I just said type not copy.Make sure the code does what you have expected.Play with the code,make changes run and pacify yourself that now you have actually understood.

4.Think of Similar Examples and write your Code.
    Once you have understood the example codes, think of similar scenarios and try writing code to fulfill your expectation.You have any ideas,no ? the ideas need not be big,still wondering what to code, search for other example codes from tutorials or books and go on with it.

5.Learn Debugging
    Good Programmers use Debuggers.Stepping through code line by line is the best way to trace the execution flow.Be familiar with the debugging tool you can use in the IDE. You might find using the debugger boring or time consuming but after few debugging you will find it comfortable and fast and know that it is the best friend for the programmer.

6.Stay Hungry, Learn More
    Don't be satisfied,go for more.We can find many tutorials floating over the internet and some are really good and can help you understand even better and learn more.If you found difficulties search over and over and still you couldn't ask someone which is available to you and have a better understanding on the topic. But don't just rush to ask at once.

Pivot in Oracle for Dynamic Columns

2017-02-12T00:12:00.002-08:00

Pivot in SQL refers to the change of rows into columns based on specific constraints.
An example of pivot could be the transpose of matrix.
Example:
a matrix containing day as 1st row and sales as 2nd row for specific day

sun 10
mon 20
tue 30
The transpose of the above matrix would be

sun mon tue
10 20 30

This is an example scenario of pivot in sql.

Now, Lets get on to the actual tables in database and see how we can use pivot .

Starting with a fictional scenario,
assume a table which contains two columns DAYS and SALES.

CREATE TABLE TEST.DAILY_SALES
(
DAYS VARCHAR2(10),
SALES NUMBER
)

insert into DAILY_SALES('SUN',10);
insert into DAILY_SALES('MON',20);
insert into DAILY_SALES('TUE',15);
insert into DAILY_SALES('WED',25);
insert into DAILY_SALES('THU',10);
insert into DAILY_SALES('FRI',30);
insert into DAILY_SALES('SAT',5);

Now when we execute the following select statement
select * from TEST.DAILY_SALES
we get the output as

Now lets select data using pivot
run the following script :

select * from TEST.DAILY_SALES
pivot(max(SALES) for days in (
'SUN','MON','TUE','WED','THU','FRI','SAT'
)
)
or using alias for columns

select * from TEST.DAILY_SALES
pivot(max(SALES) for days in (
'SUN' AS "SUN",'MON' AS "MON",'TUE' AS "TUE",'WED' AS "WED",'THU' AS "THU",'FRI' AS "FRI",'SAT' AS "SAT"
)
)

The out put result is as :

Here we get the different days as column names and sales as data for the specific column.

I hope I could clarify purpose of pivot and its basic syntax is clear by now.

Login Sequence Diagram

2017-02-12T00:11:00.001-08:00

Diagramatic representation of the interaction between processes in their own order is
a Sequence Diagram.
A simple Sequence diagram for login is shown below:

Short descriptions on notations used in the above diagram.

Actor:
An actor is an entity that interacts with the system
(can be human or any other process or entity that interacts with the system ).

Call Message :
Represents the forward communication between the entities .

Return Message :
Represents the message passed back to the caller.

Function in Razor view (@helper in razor)

2015-03-31T10:43:00.001-07:00

We can create function in cshtml by using @helper syntax

syntax:
@helper <FunctionName>(paramtype param1)
{
//your custom logic
}
Here the function is same as the one we write in class file except "@helper" .
This function can be invoked from any where in the view simply like this
@FunctionName(param1);

@helper syntax enables in code reusability
scenario : Following code implements recursive function using @helper in view

@helper Recurson(IEnumerable<Menu> nodes, int? parentId)
{
if (nodes.Any(n => n.ParentId == parentId))
{
<ul>
@foreach (var node in nodes.Where(n => n.ParentId == parentId))
{
<li>
@node.Name
@Recursion(node.Menus, node.Id)
</li>
}
</ul>
}
}
@Recurson(Model.Menus, Model.Id)

In Above Code Menu Contains hierarchical data which will be iterated over to generate unordered list of the data.

For Complete working code please refer to my post : Implementing JsTree in Asp.net MVC

work out with SignalR

2013-04-06T12:15:00.001-07:00

In this post i will be talking how we can use signalR for real time web application with a demo chat application.
If you are reading this post and don't know about installing the required files please have a look at my previous post.
http://mesushil.blogspot.com/2013/04/introducing-signalr.html

here i am modifying the default asp.net template about.aspx page for the demo.

Firstly include the script in the .aspx page .
the second js i have included here is the js downloaded by the nuget.
the third file is generated at run time including the hubs declared in the server.
check the browser to ensure these files are loaded in the browser.

the image above is the part of hubs.js generated dynamically.
now lets create hub in the server.for this lets include a class file to the solution.

To create the hubs in server add the namespace as the first two lines above.
hubName in line 9 is what we will be referring in client side js to communicate with the server.
and the next is the method which i will invoke from client side to notify all the users connected to the hub.

now moving to the client side.

referring the image above:
firstly we need bind the hub we have created in the server(line 31).
then to communicate with the server hub we need to establish connection(line 35).
after we have connected with the hub we are ready to communicate with the server.
(line 46) invokes the BroadCast message in the server and here i have passed two parameters.

similarly ,the server can also invoke the method in the client .
(line 49) is invokable by the server.
If you refer to the second image the client method is invoked from the server side.
i.e when an event occurs in the sever side the server is able to push messege to the client.
but remember don't have the same methods in client and server.

That's all we need to achieve the real time functionality using signalR.
I haven't described the different terms in signalR and the transportation available
but hope this helps you go with a functional start.

The demo project is hosted in github and you can download it from here:
https://github.com/zeewons/SignalRDemo

Reference:
https://github.com/SignalR/SignalR/

This post is based on my knowledge and may not be the accurate solution or may change over time.
comments are welcome
Thanks for your time.
Regards,
sushil

Introducing SignalR

2013-04-02T11:41:00.002-07:00

Introduction:
Asp.net signalR is an open source library for asp.net developers.it is used to implement real time functionality in web application.
requirements:
signalR is not included in visual studio so far(vs 10 and vs 12) by default.It can be implemented in .net framework 4.0 and higher.
so you need vs 2010 or vs 2012 to start taking the advantage of signalR.

I will guide you trough the installation of signalR for your project .
Lets get ready with the visual studio 2010 or 2012.
I am going to use visual studio 2012 here.

Firstly open up a new project.
now open a Package Manager Console.
if you didn't find it click View and go over to other window you find it there or
go to Tools>Library Package Manager Console >Package Manager Console

make a command in console :Install-Package Microsoft.AspNet.signalR

Scroll down the generated text in console few files are downloaded which contains the asp.net server side
signaR and client side signalR js along its dependency files .
I won't be elaborating it but do give it a glance on your console.
the references added to the project look something like this

Ah ! i just forget to tell about nuget packages.
if yo have time go through this link:
http://docs.nuget.org/docs/start-here/overview
and for a first quick grasp
nuget is a visual studio extension that makes it easy to add,remove and update libraries.....
I have just installed a signalR package from nuget.

after the successful installation it creates a folder (packages) below the your project solution.
if you can't see it open up the solution in folder explorer.

Now we have all the required files we need for our project.

You are ready to go with the signalR in your project.

The use of signalR with a simple demo application will be in my next post.

This post is based on my knowledge and may not be the accurate solution or may change over time.
comments are welcome
Thanks for your time.
Regards,
sushil