I suggest you read the documentation on how to bind the grid, and make sure you understand exactly how it works.
I already explained to you in another thread how to do it (http://xceed.com/CS/forums/thread/12649.aspx), so it is difficult to add to that.
As for the WinComboBox, I suggest you create a simple sample application, and set one up in it. Then when it works, rebuild you grid as you want it, one piece at a time, until you get where you want, making sure everything you add is not breaking anything. This way you should be able to resolve your issues.
One more thing that can help you with the WinComboBox is to make the debugger to break on all exceptions (because I suspect there is an exception that is thrown).
In Visual Studio, go to Debug Menu -> Exceptions -> Common Language Runtime Exception, then select the “Thrown” CheckBox.
Make sure the “Enable Just My Code” CheckBox is unselected (Tools Menu -> Options -> Debugging -> General).
This will make sure that no exceptions are swallowed by the grid or the .NET framework, and that the debugger will break in any part of the code, not just yours.
Imported from legacy forums. Posted by André (had 536 views)