private void signalModelLibrary_MouseDown( object sender, MouseEventArgs e )
{
TreeNode node = signalModelLibrary.GetNodeAt( e.X, e.Y );
if (node != null
&& node.Parent != null
&& node.Parent.Tag is XmlElement )
{
XmlElement parent = node.Parent.Tag as XmlElement;
string data = parent.LocalName + "|" + node.Text;
signalModelLibrary.SelectedNode = node;
signalModelLibrary.DoDragDrop(data, DragDropEffects.Copy);
}
}