private void thêmToolStripMenuItem_Click(object sender, EventArgs e)
        {
            dtgv.CurrentCell = dtgv.Rows[0].Cells[0];
            int    id     = 0;
            string tenban = null;
            string status = null;

            for (int i = 0; i < dtgv.RowCount - 1; i++)
            {
                id     = Int32.Parse(dtgv.Rows[i].Cells[0].Value.ToString());
                tenban = dtgv.Rows[i].Cells[1].Value.ToString();
                status = dtgv.Rows[i].Cells[2].Value.ToString();
                webservice.updateData(id, tenban, status);
            }

            MessageBox.Show("Update success");

            loadData();
        }