Hi Lim,
When you have the ListBoxSelectionMode set to anything other than None, then this will prevent the default behavior from working. The reason is that it allows only row based selections and preventing the columns from getting selected. Hence, you cannot able to select columns.
As a workaround, you handle the CellClick event and explicitly select the column if you click a header. In this way you can select the column when the ListBoxSelectionMode is set. Below is the code snippet.
void gridControl1_CellClick(object sender, GridCellClickEventArgs e)
{
if(e.RowIndex == 0 && e.ColIndex > 0)
this.gridControl1.Selections.Add(GridRangeInfo.Col(e.ColIndex));
}
Regards,
Rajagopal