private void btnLuu_Click(object sender, EventArgs e)
        {
            if (!Check())
            {
                return;
            }

            try
            {
                if (tinh_trang == "them")
                {
                    KHU_VUC kv = new KHU_VUC
                    {
                        Ma_Khu_Vuc = txtMaKhuVuc.Text,
                        Ten_Khu_Vuc = txtTenKhuVuc.Text,
                        Ghi_Chu = txtGhiChu.Text
                        //Ghi_Chu = txtTest.Text
                    };
                    db.KHU_VUCs.InsertOnSubmit(kv);
                }
                else
                {
                    var kv = (from k in db.KHU_VUCs
                              where k.Ma_Khu_Vuc == txtMaKhuVuc.Text
                              select k).FirstOrDefault();

                    kv.Ten_Khu_Vuc = txtTenKhuVuc.Text;
                    kv.Ghi_Chu = txtGhiChu.Text;
                    //kv.Ghi_Chu = txtTest.Text;
                }

                db.SubmitChanges();
                RaiseReloadEventHander();
                Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }
 partial void UpdateKHU_VUC(KHU_VUC instance);
 partial void DeleteKHU_VUC(KHU_VUC instance);
 partial void InsertKHU_VUC(KHU_VUC instance);