private void cbRoom_TextChanged_1(object sender, EventArgs e) { DataTable c = new DataTable(); c = cntrl_sell.check_room(cbRoom.Text); dgvRoomCheck.DataSource = c; if (c.Rows.Count > 0) { dgvRoomCheck.Visible = true; String[] header = { "ລະຫັດຫ້ອງ", "ຫ້ອງເບີ" }; cntrl_col.change_columnsname(dgvRoomCheck, header); } else { dgvRoomCheck.Visible = false; } if (cbRoom.Text == "") { dgvRoomCheck.Visible = false; } }