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

發行項
08/12/2011

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：FirstNode、LastNode、NextNode、PrevNode 和 Parent。 Parent 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

建立測試每個節點的遞迴程序 (C# 和 C++ 中為遞迴方法)。

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();
      }
   }

共用方式為

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

若要逐一查看 TreeView 控制項的所有節點

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