User Control: User Control is the custom, reusable controls. User Controls offers a way to partition and reuse User Interface (UI) functionality across ASP.NET Applications. Advantages of User Control: • Code Reuse. • Cache the output of the control independently using technique called fragment caching. This will improve performance if used appropriately. • Can program against any properties declared in the control, just like ASP.NET web controls. Disadvantages of User Control: • User Controls can be instantiated in the pages that resides in the same web application. If you want to use across applications, you need to place same .ascx control in each application. • Can't hide code of user controls like server controls by compiling into an assembly. Adding User Controls to an WebForms Page: At the top of the .aspx page, add the below line above tag. <!--Register TagPrefix="Test" TagName="TestControl" Src="Test.ascx"--> This d...