C#.net Tutorials, Material, Interview Questions, WCF, Windows Services, Webs services, ASP.NET, Session Management, MSMQ, COM and more.

example post

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 20 Sep 2012 06:24:00 +0000

wcf

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 21 Jun 2012 10:44:00 +0000

Without losing user requested data, how can we do RedirectToAction in ASP.NET MVC

noreply@blogger.com (Ranga Rajesh Kumar) — Fri, 20 Apr 2012 02:53:00 +0000

When we are using ASP.NET MVC there should be some situations where we can require RedirectToAction.

Example: If we get any validation errors after form submission, we need to redirect back. that time it will reflect URL of the form, not action page.

using below code we can able to maintain original posted data as well as validation purpose. For this you can use RedirectToAction() method. we you use viewData parameter, all of the post parameters will be changed to Get parameters.

For this complex situaltion we can use TempData property for storing required request components.

Example:

public ActionResult SendData()
{
    TempData["form"] = Request.Form;
    return this.RedirectToAction(a => a.Form());
}

Then in your "Form" action you can go:

public ActionResult Form()
{
    /* Declare viewData etc. */

    if (TempData["form"] != null)
    {
        /* Cast TempData["form"] to 
        System.Collections.Specialized.NameValueCollection 
        and use it */
     }
     return View("Form", viewData);
 }

Replacing content controls in the word document by using OPENXML 2.0 concept

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 29 Dec 2011 12:11:00 +0000

create one

string strFilePath = Server.MapPath("template.docx");
        string docOutputPath = @"d:\output.docx";
        File.Copy(strFilePath, docOutputPath);
        using (WordprocessingDocument myDocument = WordprocessingDocument.Open(docOutputPath, true))
        {

           string newXml = "<root>" +
                        "<SdkName>asdf</SdkName>" +
                        "<Version>1.0</Version>" +
                        "</root>";
             //AddCustomXMLPart() 
            MainDocumentPart main = myDocument.MainDocumentPart;
            main.DeleteParts<CustomXmlPart>(main.CustomXmlParts);

            //add and write new XML part
            CustomXmlPart customXml = main.AddCustomXmlPart(CustomXmlPartType.CustomXml);
            using (StreamWriter ts = new StreamWriter(customXml.GetStream()))
            {
                ts.Write(newXml);
            }
        }

Reading and writing using OpenXML in the word file in c#.net

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 29 Dec 2011 12:09:00 +0000

        //***************reading and writing using OpenXML in the word file***************

        string strFilePath = @"d:\rentFormat1.docx";
        using (WordprocessingDocument myDocument = WordprocessingDocument.Open(strFilePath, true))
        {
            Body body = myDocument.MainDocumentPart.Document.Body;
            Paragraph para = body.AppendChild(new Paragraph());
            Run run = para.AppendChild(new Run());
            run.AppendChild(new Text("this is another paragraph"));
            string content = body.InnerText;
        }

Reading word document using openXML

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 29 Dec 2011 12:08:00 +0000

        //************************Reading word document using openXML**********************

        string strFilePath = @"d:\rentFormat1.docx";
        using (WordprocessingDocument myDocument = WordprocessingDocument.Open(strFilePath, true))
        {
            Body body = myDocument.MainDocumentPart.Document.Body;
            string strBody = body.InnerText;
        }

creation of word document using openXML concept

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 29 Dec 2011 12:07:00 +0000

        //******************************creation of word document using openXML concept**************************

        string fileName = @"D:\rentformat1.docx";
        using (WordprocessingDocument myDocument = WordprocessingDocument.Create(fileName, WordprocessingDocumentType.Document))
        {
            MainDocumentPart mainPart = myDocument.AddMainDocumentPart();
            mainPart.Document = new Document();
            Body body = mainPart.Document.AppendChild(new Body());
            Paragraph para = body.AppendChild(new Paragraph());
            Run run = para.AppendChild(new Run());

            run.AppendChild(new Text("hello, world"));
        }

Reading RSS Feeds in ASP.net with proxy set up

noreply@blogger.com (Ranga Rajesh Kumar) — Fri, 25 Nov 2011 05:18:00 +0000

<body>
<form id="form1" runat="server">
<div>
</div>
<table cellpadding="0" cellspacing="0">
<tr>
<td>
<table class="NormalText" runat="server" id="tbl_Feed_Reader" cellpadding="0" cellspacing="0">
</table>
</td>
</tr>
</table>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" />
</form>
</body>

protected void Button1_Click(object sender, EventArgs e)
{
int proxyValue = 8080;

WebProxy proxyObject = new WebProxy("http://proxy:8080/",true);
proxyObject.Credentials = CredentialCache.DefaultCredentials;

WebRequest MyRssRequest = WebRequest.Create("http://www.csharp-dotnet-interview-questions.blogspot.com/feeds/posts/default?alt=rss");
MyRssRequest.Proxy = proxyObject;
WebResponse MyRssResponse = MyRssRequest.GetResponse();
Stream MyRssStream = MyRssResponse.GetResponseStream();
// Load previously created XML Document
XmlDocument MyRssDocument = new XmlDocument();
MyRssDocument.Load(MyRssStream);
XmlNodeList MyRssList = MyRssDocument.SelectNodes("rss/channel/item");

string sTitle = "";
string sLink = "";
string sDescription = "";
// Iterate/Loop through RSS Feed items
for (int i = 0; i < MyRssList.Count; i++)

{
XmlNode MyRssDetail;
MyRssDetail = MyRssList.Item(i).SelectSingleNode("title");
if (MyRssDetail != null)
sTitle = MyRssDetail.InnerText;
else
sTitle = "";
MyRssDetail = MyRssList.Item(i).SelectSingleNode("link");
if (MyRssDetail != null)
sLink = MyRssDetail.InnerText;
else
sLink = "";
MyRssDetail = MyRssList.Item(i).SelectSingleNode("description");
if (MyRssDetail != null)
sDescription = MyRssDetail.InnerText;
else
{
sDescription = "";
}

// Now generating HTML table rows and cells based on Title,Link & Description

HtmlTableCell block = new HtmlTableCell();

block.InnerHtml = "<span style='font-weight:bold'><a href='" + sLink + "' target='new'>"+ sTitle + "</a></span>";

HtmlTableRow row = new HtmlTableRow();

row.Cells.Add(block);

tbl_Feed_Reader.Rows.Add(row);

HtmlTableCell block_description = new HtmlTableCell();

block_description.InnerHtml = "<p align='justify'>" + sDescription + "</p>";

HtmlTableRow row2 = new HtmlTableRow();

row2.Cells.Add(block_description);

tbl_Feed_Reader.Rows.Add(row2);

}

}

how to get download dialog box for pdf file while using asp.net

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 24 Nov 2011 10:07:00 +0000

string filepath = "print.pdf";
string filename = "ranga.pdf";
Response.ContentType = "pdf";
Response.AppendHeader("Content-Disposition", "attachment; filename=" + filename);
Response.TransmitFile(filepath);
Response.End();

OOPS Dotnet Frequently asked interview questions

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 24 Nov 2011 09:00:00 +0000

18. List out some of the exception classes in C#?
Answer :
Common Exception Classes :
The following exceptions are thrown by certain C# operations.
System.OutOfMemoryException Thrown when an attempt to allocate memory (via new) fails.
System.StackOverflowException Thrown when the execution stack is exhausted by having too many pending method calls; typically indicative of very deep or unbounded recursion.
System.NullReferenceException Thrown when a null reference is used in a way that causes the referenced object to be required.
System.TypeInitializationException Thrown when a static constructor throws an exception, and no catch clauses exists to catch in.
System.InvalidCastException Thrown when an explicit conversion from a base type or interface to a derived types fails at run time.
System.ArrayTypeMismatchException Thrown when a store into an array fails because the actual type of the stored element is incompatible with the actual type of the array.
System.IndexOutOfRangeException Thrown when an attempt to index an array via an index that is less than zero or outside the bounds of the array.
System.MulticastNotSupportedException Thrown when an attempt to combine two non-null delegates fails, because the delegate type does not have a void return type.
System.ArithmeticException A base class for exceptions that occur during arithmetic operations, such as DivideByZeroException and OverflowException.
System.DivideByZeroException Thrown when an attempt to divide an integral value by zero occurs.
System.OverflowException Thrown when an arithmetic operation in a checked context overflows.

19. Can you tell me about Array Covariance?
Answer :
For any two reference-types A and B, if an implicit reference conversion or explicit reference conversion exists from A to B, then the same reference conversion also exists from the array type A[R] to the array type B[R], where R is any given rank-specifier (but the same for both array types). This relationship is known as array covariance. Array covariance in particular means that a value of an array type A[R] may actually be a reference to an instance of an array type B[R], provided an implicit reference conversion exists from B to A.
Because of array covariance, assignments to elements of reference type arrays include a run-time check which ensures that the value being assigned to the array element is actually of a permitted type

20. What are Labeled statements?
Answer :
A labeled-statement permits a statement to be prefixed by a label. Labeled statements are permitted blocks, but are not permitted as embedded statements.
labeled-statement:
identifier : statement
A labeled statement declares a label with the name given by the identifier. The scope of a label is the block in which the label is declared, including any nested blocks. It is an error for two labels with the same name to have overlapping scopes.
A label can be referenced from goto statements within the scope of the label. This means that goto statements can transfer control inside blocks and out of blocks, but never into blocks

21. Do you Know about Versioning?
Answer :
Versioning is the process of evolving a component over time in a compatible manner. A new version of a component is source compatible with a previous version if code that depends on the previous version can, when recompiled, work with the new version. In contrast, a new version of a component is binary compatible if a program that depended on the old version can, without recompilation, work with the new version.Most languages do not support binary compatibility at all, and many do little to facilitate source compatibility. In fact, some languages contain flaws that make it impossible, in general, to evolve a class over time without breaking at least some client code.

22. What are Deligates ?
Answer :

Delegates enable scenarios that C++ and some other languages have addressed with function pointers. Unlike function pointers, delegates are object-oriented, type-safe, and secure.
Delegates are reference types that derive from a common base class: System.Delegate. A delegate instance encapsulates a method—a callable entity. For instance methods, a callable entity consists of an instance and a method on the instance. For static methods, a callable entity consists of a class and a static method on the class.
An interesting and useful property of a delegate is that it does not know or care about the type of the object that it references. Any object will do; all that matters is that the method’s signature matches the delegate’s. This makes delegates perfectly suited for “anonymous” invocation. This is a powerful capability.
There are three steps in defining and using delegates: declaration, instantiation, and invocation. Delegates are declared using delegate declaration syntax.
delegate void SimpleDelegate();
declares a delegate named SimpleDelegate that takes no arguments and returns void.

Dotnet OOPS interview questions

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 24 Nov 2011 08:52:00 +0000

8. What’s the difference between an interface and abstract class?
Answer :

In an interface class, all methods are abstract - there is no implementation. In an abstract class some methods can be concrete. In an interface class, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers.

9. How is method overriding different from method overloading?
Answer :
When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.
10. If a base class has a number of overloaded constructors, and an inheriting class has a number of overloaded constructors; can you enforce a call from an inherited constructor to a specific base constructor?
Answer :

Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.

11. What are the different ways a method can be overloaded?
Answer :
Different parameter data types, different number of parameters, different order of parameters.

12. Can you prevent your class from being inherited by another class?
Answer :
Yes. The keyword “sealed” will prevent the class from being inherited.

13. What’s the C# syntax to catch any possible exception?
Answer :
A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}

14. What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?
Answer :
The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element’s object, resulting in a different, yet identacle object.

15. What’s the advantage of using System.Text.StringBuilder over System.String?
Answer :
StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time a string is changed, a new instance in memory is created.

16. What’s the difference between System.String and System.Text.StringBuilder classes?
Answer :
System.String is immutable. System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.

17. What does the term immutable mean?
Answer :
The data value may not be changed. Note: The variable value may be changed, but the original immutable data value was discarded and a new data value was created in memory.

OOPS interview questions for dotnet(c#.net)

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 24 Nov 2011 08:46:00 +0000

1. You have one base class virtual function how will call that function from derived class?
Answer :

        class a
        {
            public virtual int m()
            {
                return 1;
            }
        }
        class b : a
        {
            public int j()
            {
                return m();
            }
        }



2. Can we call a base class method without creating instance?

Answer :



Its possible If its a static method.

Its possible by inheriting from that class also.

Its possible from derived classes using base keyword.



3. What is Method Overriding? How to override a function in C#?

Answer :



Use the override modifier to modify a method, a property, an indexer, or an event. An override method provides a new implementation of a member inherited from a base class. The method overridden by an override declaration is known as the overridden base method. The overridden base method must have the same signature as the override method.

You cannot override a non-virtual or static method. The overridden base method must be virtual, abstract, or override



4. What’s an abstract class?

Answer :



A class that cannot be instantiated. An abstract class is a class that must be inherited and have the methods overridden. An abstract class is essentially a blueprint for a class without any implementation.



5. When do you absolutely have to declare a class as abstract?

Answer :

1. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden.

2. When at least one of the methods in the class is abstract.



6. What is an interface class?

Answer :



Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes.

jQuery Confirm Dialog plugin

noreply@blogger.com (Ranga Rajesh Kumar) — Wed, 23 Nov 2011 09:07:00 +0000

$(".confirm").easyconfirm();
 $("#alert").click(function() {
  alert("You approved the action");
 });

<a href="#" class="confirm" id="alert">Normal test</a>
 <a href="?confirm=true" class="confirm">Normal test with a link</a>
 <a href="?confirm=true" class="confirm" title="Are you sure you want to click on this link?">Normal test with a link</a>

how to alert using javascript

noreply@blogger.com (Ranga Rajesh Kumar) — Wed, 23 Nov 2011 09:02:00 +0000

<html>
<body>
<input type="text" />
<script language="javascript">alert('hello');</script>
</body>
</html>

Structs (C# Programming Guide)

noreply@blogger.com (Ranga Rajesh Kumar) — Tue, 04 Oct 2011 12:00:00 +0000

Structs (C# Programming Guide)

public struct PostalAddress

{

// Fields, properties, methods and events go here...

}

Structs share most of the same syntax as classes, although structs are more limited than classes:

· Within a struct declaration, fields cannot be initialized unless they are declared as const or static.

· A struct may not declare a default constructor (a constructor without parameters) or a destructor.

· Structs are copied on assignment. When a struct is assigned to a new variable, all the data is copied, and any modification to the new copy does not change the data for the original copy. This is important to remember when working with collections of value types such as Dictionary<string, myStruct>.

· Structs are value types and classes are reference types.

· Unlike classes, structs can be instantiated without using a new operator.

· Structs can declare constructors that have parameters.

· A struct cannot inherit from another struct or class, and it cannot be the base of a class. All structs inherit directly from System.ValueType, which inherits from System.Object.

· A struct can implement interfaces.

· A struct can be used as a nullable type and can be assigned a null value.

Inheritance (C# Programming Guide)

noreply@blogger.com (Ranga Rajesh Kumar) — Mon, 03 Oct 2011 12:02:00 +0000

Inheritance, together with encapsulation and polymorphism, is one of the three primary characteristics (or pillars) of object-oriented programming. Inheritance enables you to create new classes that reuse, extend, and modify the behavior that is defined in other classes. The class whose members are inherited is called the base class, and the class that inherits those members is called the derived class.

Note

Structs do not support inheritance, but they can implement interfaces.

Conceptually, a derived class is a specialization of the base class. For example, if you have a base class Animal, you might have one derived class that is named Mammal and another derived class that is named Reptile. A Mammal is an Animal, and a Reptile is an Animal, but each derived class represents different specializations of the base class.

Extension Methods in C#.NET

noreply@blogger.com (Ranga Rajesh Kumar) — Sun, 02 Oct 2011 11:58:00 +0000

You can "extend" a class without creating a derived class by creating a separate type whose methods can be called as if they belonged to the original type.

Anonymous Types in C#.NET

noreply@blogger.com (Ranga Rajesh Kumar) — Sat, 01 Oct 2011 11:56:00 +0000

In situations where it is not convenient or necessary to create a named class, for example when you are populating a list with data structures that you do not have to persist or pass to another method, you use anonymous types.

Object Initializers in c#.net

noreply@blogger.com (Ranga Rajesh Kumar) — Fri, 30 Sep 2011 11:53:00 +0000

Object Initializers

You can instantiate and initialize class or struct objects, and collections of objects, without explicitly calling their constructor.

Partial Types in c#.net

noreply@blogger.com (Ranga Rajesh Kumar) — Thu, 29 Sep 2011 11:51:00 +0000

Partial Types

You can define part of a class, struct or method in one code file and another part in a separate code file.

Static Types in C#.net

noreply@blogger.com (Ranga Rajesh Kumar) — Wed, 28 Sep 2011 11:50:00 +0000

Classes (but not structs) can be declared as static. A static class can contain only static members and cannot be instantiated with the new keyword. One copy of the class is loaded into memory when the program loads, and its members are accessed through the class name. Both classes and structs can contain static members.

Nested Types in C#.net

noreply@blogger.com (Ranga Rajesh Kumar) — Tue, 27 Sep 2011 11:50:00 +0000

A class or struct can be nested within another class or struct.

Inheritance in c#.net

noreply@blogger.com (Ranga Rajesh Kumar) — Mon, 26 Sep 2011 11:47:00 +0000

Classes (but not structs) support the concept of inheritance. A class that derives from another class (the base class) automatically contains all the public, protected, and internal members of the base class except its constructors and destructors.

Classes may be declared as abstract, which means that one or more of their methods have no implementation. Although abstract classes cannot be instantiated directly, they can serve as base classes for other classes that provide the missing implementation. Classes can also be declared as sealed to prevent other classes from inheriting from them.

Difference between BasicHttpBinding and WsHttpBinding

noreply@blogger.com (Ranga Rajesh Kumar) — Sun, 25 Sep 2011 09:53:00 +0000

Difference between BasicHttpBinding and WsHttpBinding

BasicHttpBinding :

· BasicHttpBinding is there only to support the old .ASMX style of working and aimed for clients who do not have .NET 3.0 installed. So the BasicHttpBinding it’s there mainly for compatibility reasons.

· ASMX (without the WS enhancements) does not support secure messaging. When a client calls an operation on a service, all data in the payload is send as a plain XML, human readable, SOAP packet.

· It also does not support reliability and ordered delivery.

· When a call is lost somewhere, the client is not informed and just waits for a timeout and cannot know for sure if the call has arrived at the server and if the logic behind it got executed.

· Also lacking in the basic profile is ordered delivery. This means when a client fires multiple calls to the service it’s not guaranteed that they arrive in the same order. Maybe somewhere a router could drop a packet allowing the second call to arrive earlier than the retransmission of the first. This can lead to disasters, which cannot be allowed in enterprise solutions.

WSHttpBinding :

· The WSHttpBinding fully supports these requirements on security, reliability and ordered delivery. Some of them as default, others have to be configured.

· WSHttpBinding uses (as the name implies) the WS-* protocols. This results in having some additional handshake messaging and This means that not only SOAP requests are sent for the operation calls but also to have the client and service agree on some context and to inform each other on the success of the calls.

Accessibility In c#.net

noreply@blogger.com (Ranga Rajesh Kumar) — Sat, 24 Sep 2011 11:45:00 +0000

Some methods and properties are meant to be called or accessed from code outside your class or struct, known as client code. Other methods and properties might be only for use in the class or struct itself. It is important to limit the accessibility of your code so that only the intended client code can reach it. You specify how accessible your types and their members are to client code by using the access modifiers public, protected, internal, protected internal, and private.