private void AddColMenu_Click(object sender, EventArgs e) { var menuItem = (MenuItem)sender; var hitTest = (DataGridView.HitTestInfo)menuItem.Tag; AddColumnOptions opts = new AddColumnOptions(); opts.ShowDialog(this); DMSNewColumn newCol = opts.newColumn; if (newCol != null) { var defVal = opts.defaultValue; viewerTable.AddColumn(newCol, viewerTable.Columns[hitTest.ColumnIndex], defVal); DrawDataTable(); } }