private void _treeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
var selectTreeViewItem = _treeView.SelectedItem as SignatureTreeViewModel;
if (selectTreeViewItem == null) return;
_trustSignatureCollection.Clear();
_trustSignatureCollection.AddRange(selectTreeViewItem.Value.LinkItem.TrustSignatures);
_untrustSignatureCollection.Clear();
_untrustSignatureCollection.AddRange(selectTreeViewItem.Value.LinkItem.DeleteSignatures);
this.Update_Title();
}