private void btnThaydoimk_ItemClick(object sender, ItemClickEventArgs e)
 {
     frmDoimatkhau doimatkhau = new frmDoimatkhau();
     doimatkhau.Show();
 }
        private void btnThaydoimk_ItemClick(object sender, ItemClickEventArgs e)
        {
            frmDoimatkhau doimatkhau = new frmDoimatkhau();

            doimatkhau.Show();
        }