The @Register directive is used to register custom server control components in an ASP.NET page. This directive tells the compiler which control components are used in the page. For example, if we have a custom server control called “MyControl” and we want to use it in an ASP.NET page, we can add the following directive:
@Register TagPrefix=”MyControls” TagName=”MyControl” Src=”MyControl.ascx”
This directive will register the custom server control component with the tag prefix “MyControls” and the tag name “MyControl”, and the source file for the component is “MyControl.ascx”.