Filter between combo column in GDBG

In My GDBG,I have 2 combo column,after i choose the first combo column item,the second column's databound source should be filtered by the fitst combo column selected item. Which event should i use to do..? any sample?thanks!

You can do this handling a couple of events, CurrentCellChanged and CurrentCellShowingDropDown. The idea is that in CurrentCellShowingDropDown, you create a DataView filtered according to your needs, and set this DataView to be the datasource for the dropdown. Attached is a little sample. The one crucial point is that the datasource for the 'slave combo' should be the complete table that is being used to create the DataView in CurrentCellShowingDropDown.