Assembly: System.Design (in system.design.dll)
Because the UsePreviewControl property is always true, the designer uses a View control that contains a copy of the associated GridView control to generate the design-time markup. The View control does not affect any persistence for the GridView.
If the UsePreviewControl property has been overridden to return false, the designer will use the associated GridView itself to generate the design-time markup, and design-time changes to the control will persist to the page markup source.Notes to Inheritors: You can override the UsePreviewControl property to return false or to determine its value based on whether the control is marked with a class-level SupportsPreviewControlAttribute object. If the UsePreviewControl is not overridden, the GridView ignores the SupportsPreviewControlAttribute.