private void btnUserInformation_ItemClick(object sender, ItemClickEventArgs e)
        {
            Form frm = kiemtraform(typeof(frm_UserInfo));

            if (frm == null)
            {
                frm_UserInfo forms = new frm_UserInfo( );
                forms.MdiParent = this;
                forms.Show( );
            }
            else
            {
                frm.Activate( );
            }
        }
        // Chinh Sua nhan vien
        private void btn_Edit_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
        {
            frm_NewCustomer frm = new frm_NewCustomer( );

            frm.FormClosed += new FormClosedEventHandler(dongformEmployee);
            user_id         = Convert.ToInt64(grdv_Employee.GetRowCellValue(index_user, "employee_id").ToString( ));

            if (user_id != 0)
            {
                frm_UserInfo f = new frm_UserInfo( );
                f.user_id = user_id;
                f.ShowDialog( );
            }
            else
            {
                messeage.error("Không thể chỉnh sửa !");
            }
        }