private void _TableSelected() { _TableId = (int)cboTables.SelectedValue; dsGrid = DataProcs.ExecuteQuery("SELECT ColumnId, TableId, ColumnName, Expression FROM Columns WHERE TableId = " + _TableId, CommandType.Text); grdColumns.DataSource = null; grdColumns.DataMember = null; if (dsGrid.Tables[0].Rows.Count > 0) { grdColumns.DataSource = dsGrid.Tables[0]; grdColumns.Columns[0].Visible = false; grdColumns.Columns[1].Visible = false; grdColumns.Columns[2].Width = 200; grdColumns.Columns[3].Width = 490; grdColumns.Columns[2].HeaderText = "Column Name"; grdColumns.Columns[3].HeaderText = "Expression"; } // THIS IS THE PART THAT DOES NOT WORK dsTables = DataProcs.ExecuteQuery("SELECT TableId, QueryName FROM Tables ORDER BY TableName"); DataGridViewComboBoxColumn colTables = new DataGridViewComboBoxColumn(); colTables.Name = "colTables"; colTables.DataSource = dsTables.Tables[0]; grdColumns.Columns.Add(colTables); }My combo appears with nothing in it.