private void lv_angebote_DoubleClick(object sender, EventArgs e)
 {
     Dialogs.AngebotDetail tmp = new AngebotDetail((Angebot)lv_angebote.FocusedItem.Tag);
     tmp.ShowDialog();
     BindTo();
 }
 private void bn_new_angebot_Click(object sender, EventArgs e)
 {
     Dialogs.AngebotDetail tmp = new AngebotDetail();
     tmp.ShowDialog();
     BindTo();
 }