The default designer that comes with the Web Controls is great but there are times when you might need to customize it. It’s pretty easy to do. You need to extend the web control and explicitly set the Designer Attribute for the extended web control. For example, in the following sample a GridView and its designer is extended.

[Designer(typeof(CustomControls.CustomGridDesigner))] [ToolboxData("")][Serializable] public class CustomGrid : GridView {} // Override members of the GridViewDesigner. [ReflectionPermission(SecurityAction.Demand, Flags = ReflectionPermissionFlag.MemberAccess)]public class CustomGridDesigner : GridViewDesigner { }