Here is code to get the column in TableControlCurrentCellValidating.
private void gridGroupingControl1_TableControlCurrentCellValidating(object sender, GridTableControlCancelEventArgs e)
{
GridCurrentCell cc = e.TableControl.CurrentCell;
GridTableCellStyleInfo style = e.TableControl.Table.GetTableCellStyle(cc.RowIndex, cc.ColIndex);
GridColumnDescriptor cd = style.TableCellIdentity.Column;
if(cd != null)
{
// cd is the columndescriptor
Console.WriteLine(cd.Name);
}
}