private void btnAdd_Click(object sender, EventArgs e)
        {
            DtoWarehouse w = new DtoWarehouse();

            w.MaKho  = txtWarehouseID.Text.ToString();
            w.TenKho = txtWarehouseName.Text.ToString();
            w.GhiChu = txtNote.Text.ToString();

            if (_isEditing)
            {
                if (_bllWarehouse.EditWarehouse(w))
                {
                    MessageBox.Show(Constants.MsgNotificationEditSuccessfuly);
                }
                else
                {
                    MessageBox.Show(Constants.MsgAlreadyExist);
                }
                btnCancel.PerformClick();
                return;
            }
            if (_bllWarehouse.AddWarehouse(w))
            {
                MessageBox.Show(Constants.MsgNotificationSuccessfuly);
            }
            else
            {
                MessageBox.Show(Constants.MsgAlreadyExist);
            }
        }