private void btnXoaDU_Click(object sender, EventArgs e)
        {
            try
            {
                using (var k = new AppCode.QuanCafe())
                {
                    foreach (DataGridViewRow row in grvDSDoUong.Rows)
                    {
                        DataGridViewCheckBoxCell chk = (DataGridViewCheckBoxCell)row.Cells[0];

                        if (chk.Value != ckbChonDoUong.TrueValue)
                        {
                            k.XoaDoUong(int.Parse(grvDSDoUong.Rows[row.Index].Cells[1].Value.ToString().Trim()));
                        }
                    }
                    LoadDSDoUong();
                }
            }
            catch
            {
                return;
            }
        }