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HOW TO:逐一查看 Windows Form TreeView 控制項的所有節點

有時候這在檢查 Windows Form TreeView 控制項的每個節點,以便對節點值進行某些計算時非常有用。 這項作業可以利用逐一查看每個樹狀集合物件 (Collection) 中每個節點的遞迴程序 (C# 和 C++ 中為遞迴方法) 來完成。

樹狀檢視中的每個 TreeNode 物件都有屬性,您可以使用這些屬性來巡覽樹狀檢視:FirstNodeLastNodeNextNodePrevNodeParentParent 屬性的值是目前節點的父節點。 如果有子節點時,目前節點的子節點將列於 Nodes 屬性中。 TreeView 控制項本身具有 TopNode 屬性,這是整個樹狀檢視的根 (Root) 節點。

若要逐一查看 TreeView 控制項的所有節點

  1. 建立測試每個節點的遞迴程序 (C# 和 C++ 中為遞迴方法)。

  2. 呼叫此程序。

    下列範例顯示如何列印每個 TreeNode 物件的 Text 屬性:

    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();
          }
       }
    

請參閱

概念

遞迴程序 (Visual Basic)

其他資源

TreeView 控制項 (Windows Form)