Mar 27, 2008 04:34 PM|JByrd2007|LINK
You can use a preprocessor directive to trigger a compile-time error when a value is not defined for the property of the control.
In this case, I overrode the RenderContents method of the control and added a check of the property. This example will generate an error if you compile a page with the control if the value of the property (in this case a string) is null/empty:
(other code to render the control's output here)...
Hope this helps!