public void LoadComboboxSite()
{
    List<SITE> bp = new List<SITE>();
    bp = BUS.BUS_Site.compoboxSite();
    for (int i = 0; i < bp.Count; i++)
    {

        cmbSite.Items.AddRange(bp[i].ID_SITE, bp[i].TEN_SITE);


    }
    cmbSite.SelectedItem = bp[0].ID_SITE;

}