During the constructor of the editor that as the ultragrid, I want to create the dropdown lists for each column that needs it. Currently I've assigned a comboEditor to each column and I configure those at run time, but would be nice if I can just configure the column directly and use the native drop down behavior of the grid without having to use additional controls.
Use a ValueList.
var list = grid.DisplayLayout.ValueLists.Add();
list.ValueListItems.Add(...
grid.DisplayLayoutBands[0].Columns[key].ValueList = list.
You can also cell a different value list for each cell, and use a BindableValueList that can get a data source.
The quick help on grid.DisplayLayout.Bands[0].Columns[key].ValueList say the property is read only.
However I implemented your suggestion and it works great. I'm slightly disturbed that the hot tip and documentation says it is read only, so I'll need to test this heavily, but otherwise this is exactly what I was after.