How to search for a TreeNodeAdv in the WinForms TreeViewAdv?

private TreeNodeAdv Search(TreeNodeAdv tna)
{
   if(tna.Text == text)
   {
      return node;
   }
   //Checks whether the node contains child node or not. If yes, foreach statement will iterate through all sibling nodes of this node.
   if(tna.HasChildren)
   {
      foreach(TreeNodeAdv tnac in tna.Nodes)
         Search(tnac);
   }
   if(tna.NextNode !=null)
   {
      Search(tna.NextNode);
   }
   return null;
}

Public Function Search(tna As TreeNodeAdv ) As TreeNodeADv
    If tna.Text == text Then Return node;
       'Checks whether the node contains child node or not. If yes, foreach statement will iterate through all sibling nodes of this node.
       If tna.HasChildren
           Dim tnac as TreeNodeAdv
           For Each(TreeNodeAdv tnac in tna.Nodes)
               Search(tnac)
           Next
       If Not tna.NextNode =Nothing Then Search(tna.NextNode);
              Return Nothing
End Function