class TreeViewChecked{  bool isfirst = true;  public TreeViewChecked(TreeView treeView)  {   treeView.AfterCheck += new TreeViewEventHandler(treeView_AfterCheck);   treeView.AfterSelect += new TreeViewEventHandler(treeView_AfterSelect);  }  /// <summary>  /// 點擊文字，選中checkbox  /// </summary>  /// <param name="sender"></param>  /// <param name="e"></param>  void treeView_AfterSelect(object sender, TreeViewEventArgs e)  {   if (e.Node.Checked)    e.Node.Checked = false;   else    e.Node.Checked = true;   if (isfirst)   {    isfirst = false;    e.Node.TreeView.Nodes[0].Checked = false;   }  }  /// <summary>  /// 選中子節點，勾選父節點，選中父節點，勾選子節點  /// </summary>  /// <param name="sender"></param>  /// <param name="e"></param>  void treeView_AfterCheck(object sender, TreeViewEventArgs e)  {   CheckTreeNode(e.Node);  }  /// <summary>  /// 選中子節點，勾選父節點，選中父節點，勾選子節點  /// </summary>  /// <param name="node"></param>  private void CheckTreeNode(TreeNode node)  {   node.TreeView.AfterCheck -= new TreeViewEventHandler(treeView_AfterCheck);   //如果不等于null,說明選擇的是子節點   if (node.Parent != null)   {    TreeNode parent = node.Parent as TreeNode;    //如果該節點是選中的    if (node.Checked)    {     //判斷其父節點是否被選中，如果沒有被選中則選中它     if (parent.Checked == false)     {      parent.Checked = true;     }    }    else    {     bool ischecked = false;     foreach (TreeNode child in parent.Nodes)     {      if (child.Checked)      {       ischecked = true;       break;      }     }     if (ischecked)      parent.Checked = true;     else      parent.Checked = false;    }   }//如果等于null，說明選擇的是根節點   else   {    foreach (TreeNode child in node.Nodes)    {     child.Checked = node.Checked;    }   }   node.TreeView.AfterCheck += new TreeViewEventHandler(treeView_AfterCheck);  }}