In our web application I used asp.net UltraWebGrid and Webcombo. Webcombo used as editor control for grid column.It works fine when I use webcombo with following.

Editable - false

DataValueField - CategoryID

DataTextField - CategoryName

WebGrid has columns EmpID, EmpName, CategoryID 

CategoryID (EditorControlID - WebCombo, Type - Custom).

When I used same thing with Editable - true of webcombo it gives me error DataValue and DataTextField of webcombo should be same.If I keep same value I cann't read the CategoryID/Description . I can read only one value when in grid.

For your information I handled these things at client side AfterSelectChange of web combo and assigning the id of the selected value in webcombo to Grid column(hidden) so that I can read id and description.Do you have any inbuilt .Am I doing workaround. Is it known bug...