private void btnThem_Click(object sender, EventArgs e)
        {
            FrLstNhaCCEdit frm = new FrLstNhaCCEdit();

            frm.Tag = ""; //Tín hiệu cho biết thêm mới
            frm.ShowDialog();
            HienThiLstNCC(GrNhaCC);
        }
        private void btnSua_Click(object sender, EventArgs e)
        {
            FrLstNhaCCEdit fr = new FrLstNhaCCEdit();

            fr                = new FrLstNhaCCEdit();
            fr.Tag            = this.GrNhaCC.CurrentRow.Cells["Ma_NhaCC"].Value.ToString(); //Tín hiệu sửa
            fr.txtMaNCC.Text  = this.GrNhaCC.CurrentRow.Cells["Ma_NhaCC"].Value.ToString();
            fr.txtTenNCC.Text = this.GrNhaCC.CurrentRow.Cells["Ten_NhaCC"].Value.ToString();
            fr.txtDiaChi.Text = this.GrNhaCC.CurrentRow.Cells["Dia_Chi"].Value.ToString();
            fr.txtSDT.Text    = this.GrNhaCC.CurrentRow.Cells["Sdt"].Value.ToString();
            fr.ShowDialog();
            HienThiLstNCC(GrNhaCC);
        }