If you want to display multiple foreign columns, then it is probably simpler just to use unbound columns to do this. If you want to use ComboBoxes like you are doing now, you would have to add alias columns to your sql query to get duplicate columns (with diffferent column names) in your main DataTable.
Here is a sample using unbound columns to display 2 foreign columns based on the same ID field in the main table. It shows the foreign key in the grid as well as the two additional foreign columns. This lets you edit the foreign key which adds some additional code. If you do not need this editing of the foreign key, the cm.ItemChanged event handler can be removed.
percent_8844.zip