You do it the same way by getting the renderer for the GridListControl cell. From there, you can get renderer.ListBoxPart which is teh GridListControl, and from there you get the Grid member.
The problem is that Dropdown list can vary from cell to cell which means that potentially you have to change teh headers for every cell. It would be simplest to just use a DataTable as your DataSource and to set the ColumnName to what you want to see.
If you cannot do this for some reason, then you would want to catch CurrentCellShowingDropDown and if the cell being dropped is a GridListControl cell for which you want to modify the headers, then you could subscribe to the cellRenderer.ListControlPart.Grid.PrepareViewStyleInfo event as in the sample. Then in CurrentCellDropDownCLosed, you would weant to unsubscribe to the event.
Here is code you might use to subscribe to the event.
private void gridControl1_CurrentCellShowingDropDown(object sender, GridCurrentCellShowingDropDownEventArgs e)
{
GridCurrentCell cc = this.gridControl1.CurrentCell;
if(cc.ColIndex == 1 && cc.RowIndex == 3) // the cell you want
{
GridDropDownGridListControlCellRenderer cr = this.gridControl1.CurrentCell.Renderer as GridDropDownGridListControlCellRenderer;
if(cr != null)
{
GridDropDownGridListControlPart list = (GridDropDownGridListControlPart)cr.ListControlPart;
list.Grid.PrepareViewStyleInfo += new GridPrepareViewStyleInfoEventHandler(grid_PVSI);
}
}
}