private void OKButton_Click(object sender, RoutedEventArgs e)
{
QLThuebaoDomainContext dstb = new QLThuebaoDomainContext();
int m= Convert.ToInt16(cmbloaihong.GetKeyValue(cmbloaihong.SelectedIndex).ToString());
InvokeOperation<System.Nullable<int>> p = dstb.Excute_p_suaxong119(m_so,m,App.User_name);
p.Completed += new EventHandler(Completed);
}