ASP.NET

protected void AddUnit_Click(object sender, EventArgs e)
   {
       AddParentNode();

       for (int i = 0; i <= AvailableUnitsTreeView.Nodes.Count - 1; i++)
       {
           AddUnits(AvailableUnitsTreeView.Nodes[i]);
       }


   }

private void AddParentNode()
   {
       if (SelectedUnitsTreeView.Nodes.Count== 0)
       {
           TreeNode Parentnode = new TreeNode();
           Parentnode.Text = AvailableUnitsTreeView.Nodes[0].Text;
           Parentnode.Value = AvailableUnitsTreeView.Nodes[0].Value;
           SelectedUnitsTreeView.Nodes.Add(Parentnode);
           SelectedUnitsTreeView.Nodes[0].ShowCheckBox = false;
       }


   private void AddUnits(TreeNode node)
   {
       for (int i = 0; i <= node.ChildNodes.Count-1; i++)
       {
           AddUnits(node.ChildNodes[i]);
           if (node.ChildNodes[i].Checked == true)
           {
               SelectedUnitsTreeView.Nodes.Add(node);
               SelectedUnitsTreeView.Nodes.Add(node.ChildNodes[i]);
              // AvailableUnitsTreeView.Nodes.Remove(node.ChildNodes[i]);
           }

       }

   }