Csharp: Treeview check list value

/// <summary>
         /// 選擇的節點
         /// 塗聚文 20121116
         /// 捷為工作室
         ///
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void treeView1_AfterCheck(object sender, TreeViewEventArgs e)
         {
  #region  4

             if (e.Action != TreeViewAction.Unknown)
             {

                 //Event call by mouse or key-press

                 SetNodeCheckStatus(e.Node, e.Node.Checked);

             }
             #endregion 

         }
         /// <summary>
         /// 選擇的節點
         /// </summary>
         /// <param name="tn"></param>
         /// <param name="Checked"></param>
         private void SetNodeCheckStatus(TreeNode tn, bool Checked)
         {

             if (tn == null) return;

             // Check children nodes

             foreach (TreeNode tnChild in tn.Nodes)
             {

                 tnChild.Checked = Checked;

                 SetNodeCheckStatus(tnChild, Checked);

             }

             // Set parent check status

             TreeNode tnParent = tn;

             int nNodeCount = 0;

             while (tnParent.Parent != null)
             {

                 tnParent = (TreeNode)(tnParent.Parent);

                 nNodeCount = 0;

                 foreach (TreeNode tnTemp in tnParent.Nodes)

                     if (tnTemp.Checked == Checked)

                         nNodeCount++;

                 if (nNodeCount == tnParent.Nodes.Count)

                     tnParent.Checked = Checked;

                 else

                     tnParent.Checked = false;

             }

         }

         #region  選擇的節點
         /// <summary>
         /// http://www.codeproject.com/Questions/196856/C-NET-Treeview-Node-Checked
         /// http://msdn.microsoft.com/en-us/library/system.windows.forms.treeview.aftercheck.aspx
         /// </summary>
         /// <param name="treeNode"></param>
         /// <param name="nodeChecked"></param>
         public void CheckAllChildNodes(TreeNode treeNode, bool nodeChecked)
         {
             foreach (TreeNode node in treeNode.Nodes)
             {
                 node.Checked = nodeChecked;
                 if (node.Nodes.Count > 0)
                 {
                     this.CheckAllChildNodes(node, nodeChecked);
                 }
             }
         }
         #endregion
         /// <summary>
         /// 顯示選擇的節點
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void button1_Click(object sender, EventArgs e)
         {

             DataTable dt = new DataTable();
             dt.Columns.Add("Uid", typeof(Guid));
             dt.Columns.Add("ID", typeof(int));
             dt.Columns.Add("Name", typeof(string));
             dt.Columns.Add("ParentID", typeof(int));

             List<TreeNode> selectedNodes = new List<TreeNode>();
             GetSelectedTreeNode(treeView1.Nodes, selectedNodes);
             int i = 0;
             foreach (TreeNode node in selectedNodes)
             {
                  if (!string.IsNullOrEmpty(node.ToolTipText))
                 {
                     dt.Rows.Add(new Guid(node.ToolTipText), node.Name, node.Text,node.Parent.Name);
                 }
                 i++;
             }

             dataGridView1.DataSource = dt;

         }
         /// <summary>
         /// 選擇的節點的值
         /// </summary>
         /// <param name="nodes"></param>
         /// <param name="selectedNodes"></param>
         void GetSelectedTreeNode(TreeNodeCollection nodes, List<TreeNode> selectedNodes)
         {
             foreach (TreeNode node in nodes)
             {
                 if (node.Checked)
                 {
                     selectedNodes.Add(node);
                 }
                 GetSelectedTreeNode(node.Nodes, selectedNodes);
             }
         }