如何：循环访问 Windows 窗体 TreeView 控件的所有节点

更新：2007 年 11 月

为了对节点值执行某种运算，查看 Windows 窗体 TreeView 控件中的每个节点有时是很有用的。利用递归过程（C# 和 C++ 中为递归方法）可完成此操作，该过程循环访问每个树集合中的每个节点。

树视图中的每个 TreeNode 对象都具有可用于定位树视图的属性：FirstNode、LastNode、NextNode、PrevNode 以及 Parent。Parent 属性值是当前节点的父节点。当前节点如果有子节点，则子节点将列在它的 Nodes 属性中。TreeView 控件本身具有 TopNode 属性，该属性是整个树视图的根节点。

循环访问 TreeView 控件的所有节点

1. 创建测试每个节点的递归过程（C# 和 C++ 中为递归方法）。

2. 调用该过程。

   下面的示例演示如何打印每个 TreeNode 对象的 Text 属性：

   Private Sub PrintRecursive(ByVal n As TreeNode)
      System.Diagnostics.Debug.WriteLine(n.Text)
      MessageBox.Show(n.Text)
      Dim aNode As TreeNode
      For Each aNode In n.Nodes
         PrintRecursive(aNode)
      Next
   End Sub
   
   ' Call the procedure using the top nodes of the treeview.
   Private Sub CallRecursive(ByVal aTreeView As TreeView)
      Dim n As TreeNode
      For Each n In aTreeView.Nodes
         PrintRecursive(n)
      Next
   End Sub
   

   private void PrintRecursive(TreeNode treeNode)
   {
      // Print the node.
      System.Diagnostics.Debug.WriteLine(treeNode.Text);
      MessageBox.Show(treeNode.Text);
      // Print each node recursively.
      foreach (TreeNode tn in treeNode.Nodes)
      {
         PrintRecursive(tn);
      }
   }
   
   // Call the procedure using the TreeView.
   private void CallRecursive(TreeView treeView)
   {
      // Print each node recursively.
      TreeNodeCollection nodes = treeView.Nodes;
      foreach (TreeNode n in nodes)
      {
         PrintRecursive(n);
      }
   }
   

   private void PrintRecursive(TreeNode treeNode) 
   {
      // Print the node.
      System.Diagnostics.Debug.WriteLine(treeNode.get_Text());
      MessageBox.Show(treeNode.get_Text());
      for(int i = 0; i < treeNode.GetNodeCount(false); ++i) // Print each node recursively.
      {
         PrintRecursive(treeNode.get_Nodes().get_Item(i));
      }
   }
   
   // Call the procedure using the TreeView.
   private void CallRecursive(TreeView treeView) 
   {
      // Print each node recursively.
      TreeNodeCollection nodes = treeView.get_Nodes();
      for(int i = 0; i < nodes.get_Count(); ++i)
      {
         PrintRecursive(nodes.get_Item(i));
      }
   }
   

   private:
      void PrintRecursive( TreeNode^ treeNode )
      {
         // Print the node.
         System::Diagnostics::Debug::WriteLine( treeNode->Text );
         MessageBox::Show( treeNode->Text );
   
         // Print each node recursively.
         System::Collections::IEnumerator^ myNodes = (safe_cast<System::Collections::IEnumerable^>(treeNode->Nodes))->GetEnumerator();
         try
         {
            while ( myNodes->MoveNext() )
            {
               TreeNode^ tn = safe_cast<TreeNode^>(myNodes->Current);
               PrintRecursive( tn );
            }
         }
         finally
         {
            IDisposable^ disposable = dynamic_cast<System::IDisposable^>(myNodes);
            if ( disposable != nullptr )
                     disposable->Dispose();
         }
      }
   
      // Call the procedure using the TreeView.
      void CallRecursive( TreeView^ treeView )
      {
         // Print each node recursively.
         TreeNodeCollection^ nodes = treeView->Nodes;
         System::Collections::IEnumerator^ myNodes = (safe_cast<System::Collections::IEnumerable^>(nodes))->GetEnumerator();
         try
         {
            while ( myNodes->MoveNext() )
            {
               TreeNode^ n = safe_cast<TreeNode^>(myNodes->Current);
               PrintRecursive( n );
            }
         }
         finally
         {
            IDisposable^ disposable = dynamic_cast<System::IDisposable^>(myNodes);
            if ( disposable != nullptr )
                     disposable->Dispose();
         }
      }
   

请参见

概念

递归过程

其他资源

TreeView 控件（Windows 窗体）