private void cmdEdit_Click(object sender, EventArgs e)
        {
            var frm = new FrmThemMoiKhachHang();

            frm.txtIdKhachHang.Text = Utility.sDbnull(grdkhachhang.GetValue(KskDmucKhachhang.Columns.IdKhachHang), -1);
            frm.MEnAction           = action.Update;
            frm.dt = dtDmucKhachHang;
            frm.ShowDialog();
        }
        private void cmdNew_Click(object sender, EventArgs e)
        {
            var frm = new FrmThemMoiKhachHang();

            frm.txtIdKhachHang.Text = @"-1";
            frm.MEnAction           = action.Insert;
            frm.dt = dtDmucKhachHang;
            frm.ShowDialog();
        }