How can we create custom controls in ASP.NET?
The User controls are created using .ASCX in ASP.NET. After that .ASCX file is created you need two things in order to that the ASCX can be used in the project:
1) Register the ASCX control in page using the <%@ Register directive. Example <%@ Register tagprefix="Accounting" Tagname="footer" Src="Footer.ascx" %>
2) Now to use the above accounting footer in page you can use the below directive.