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what is Extension Methods and when, where we will we use it

Posted By:      Posted Date: October 21, 2010    Points: 0   Category :ASP.Net

what is Extension Methods and when, where we will we use it

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The decorator pattern provides a formal way to add new functionality to an existing type, without sub-classing. First question: What is wrong with classical inheritance? In and of itself, nothing is wrong with the good old Is-A relationship. It is very common to derive a new class from an existing base class in order to override a few virtual members, and add a pinch of new functionality.

The Decorator Pattern & Extension Methods

Numerous design patterns exist in the software world today, and ultimately nothing is preventing you from making your own (if people buy into it or not is another question). Furthermore, there is no 'master list' of patterns that all developers agree upon. While this is true, if you pick up any book on the subject, you will find a set of very common patterns most programmers agree are very useful. Many of these patterns were first formalized in the seminal book on the subject, Design Patterns: Elements of Reusable Object-Oriented Software (aka, the Gang of Four [GOF] book; not to be confused with the UK punk band of the same name).

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Extension methods and viewstate


Hi all,

I am creating 2 extension methods for a textbox, which need to store a value and get the value, same like property, unfortunately dotnet 3.5 doesnt support extension property, so created two extension method for set and get, I am so confusing where should I store the value, like session, cache or anything else, but my recommendation to store in the viewstate object. how can I store value to viewstate. 

example my code look like

public static class clsExt
    public static bool getValue(this TextBox tb)

        return (bool)Viewstate[tb.ID];

    public static void setValue(this TextBox tb, bool value)

        Viewstate[tb.ID] = value;


Its not good idea to store session or cache, bcoz its should store only in the pagelevel, how can do this? How other textbox property storing? Could any one help on this issue please?

Thanks in advance.

Creating HTML Helpers with Extension Methods


namespace MvcLogin_Validation.Helpers
    public static class LabelExtensions
        public static string Label(this HtmlHelper helper, string target, string text)
            return String.Format("<label for='{0}'>{1}</label>", target, text);



Above is my html helper class.

<%= Html.Label("first name", "First name") %>

This is how I use it.

Now while using it I am getting an error which says, "  No overload for method 'Label' takes '2' arguments ", where as this link ( http://www.asp.net/mvc/tutorials/creating-custom-html-helpers-cs) says to do it exactly as i did.

Can anyone please guide where I am going wrong.



interesting problem about @ and extension methods.


Note , that i'm new to c# so it might not be a problem.

first , what is the exact meaning of @ in Razor ?

does it mean WebPage.Response.Write ?

next, i designed an extension method to WebPage ( by the way that is the coolest feature ever in c# )

in my Razor code , to use it in a webpage , i must write @this.MyExtensionMethod() instead of @MyExtensionMethod().

So why is it?  because @this.MyExtensionMethod() and @MyExtensionMethod() should be the same ?

here is my extension method :

using System;
using System.Web;
using System.Web.WebPages;

namespace MyExtenstionMethods{

	public static class Utility{

	    // make the page to render optional
		public static dynamic RenderOptionalPage(this WebPage Webpage ,string page="",params object[] data){

				return Webpage.RenderPage(page,data);
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<%@ Import Namespace="System.Xml" %>

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Hello people,
I'm constructing an application with Page Methods and YAHOO UI.
I'm Not using Update Panels because Page Methods are faster than Update Panel.

You can post your experiences with this feature of ASP.NET Extensions and vantages of using this type of architecture.

Thanks a lot.

Flávio Malaquias
Asp.Net Senior Developer

Multiple web methods in one transaction


Hi everyone

Sorry I am kinda new in web services, so it may sound a bit newbish question.

We have a web service that comunicates with the database and exposes web methods that enables the application to access the database. Each method does only one operation (Insert, Update or Delete). What I need to do is create a transaction that will be consisted of multiple calls to the database, meaning multiple calls of more then one web methods. Can I do that? (I read that if the web method does not throw exception - or ContextUtil.SetAbort() is not called - the transaction will be commited automatically when the web method finishes executing, which I don't want to happen because I want to call another web method in the same transaction, and then manually commit the transaction)

Thank you in advance.

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C#: Create Elegant Code With Anonymous Methods, Iterators, And Partial Classes


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Juval Lowy

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