216.

How do you register a user control?

In the containing ASP.NET Web page, create an @ Register directive that includes: 

A TagPrefix attribute, which associates a prefix with the user control. This prefix will be included in opening tag of the user control element.

A TagName attribute, which associates a name with the user control. This name will be included in the opening tag of the user control element.

A Src attribute, which defines the virtual path to the user control file that you are including.