private void btnDeleteTable_Click(object sender, EventArgs e) { int id = (int)dgvTable.CurrentRow.Cells["TableId"].Value; //update data base if (MessageBox.Show("Are you sure to delete?", "Warning!", MessageBoxButtons.OKCancel) == DialogResult.OK) { int flag = tableManager.DeleteByTableId(id); //if update success if (flag == 1) { dgvTable.DataSource = tableManager.GetAll(); } } }