How to Add or install Ajax Control Toolkit in Visual Studio?

Introduction: 

To use Ajax features in your application you need to download and Add Ajax Control Toolkit with Visual Studio: Below are the steps for this purpose:

1.  First download the latest version of the Ajax Control Toolkit from http://ajaxcontroltoolkit.codeplex.com/ . If you are using Visual Studio 2010 then use .NET 4 version of the Ajax Control Toolkit. Download toolkit according to your version of Visual Studio.
2.  After downloading the appropriate version of Ajax toolkit open the downloaded file and extract all the files.
3. Now create a new ASP.NET Web Forms project or website in visual studio. 
4.  Now open Toolbox in visual studio and create a new Toolbox tab by right-clicking the Toolbox and selecting Add Tab. Name the new tab AjaxControlToolkit or whatever you want.
5.  Right-click on this new tab and select Choose Items option. Click the Browse button and locate the folder where you extracted the Ajax Control Toolkit. Locate the AjaxControlToolkit.dll and click on the OK button to Finish. Now you can use the Ajax controls from the newly created tab AjaxControlToolkit under the toolbox.

OR

6. You also add toolkit by drag and drop. Drag AjaxControlToolkit.dll from extracted files and drop it on newly added tab in toolbox. Toolkit automatically will be added to that tab. Now you can use ajax controls in your application.