See Also: UserControlDesigner Members
There is no developer advantage to creating your own designer derived from System.Web.UI.Design.UserControlDesigner. To enhance the design-time experience for a custom control, derive your control from System.Web.UI.WebControls.CompositeControl and your designer from System.Web.UI.Design.WebControls.CompositeControlDesigner. In that case, you would not use an .ascx file for your ASP.NET markup.