TreeView.TopNode プロパティ

.NET Framework クラス ライブラリ リファレンス

TreeView.TopNode プロパティ

ツリー ビュー コントロール内で完全に表示されている最初のツリー ノードを取得します。

名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文

Visual Basic (宣言)

Public Property TopNode As
 TreeNode

Visual Basic (使用法)

Dim instance As TreeView
Dim value As TreeNode

value = instance.TopNode

instance.TopNode = value

C#

public TreeNode TopNode { get; set;
 }

C++

public:
property TreeNode^ TopNode {
    TreeNode^ get ();
    void set (TreeNode^ value);
}

J#

/** @property */
public TreeNode get_TopNode ()

/** @property */
public void set_TopNode (TreeNode value)

JScript

public function get TopNode
 () : TreeNode

public function set TopNode
 (value : TreeNode)

プロパティ値
ツリー ビュー コントロール内で完全に表示されている最初のツリー ノードを表す TreeNode。

解説

初期状態では、TopNode は、TreeView の先頭にある最初のルート ツリー ノードを返します。ただし、ユーザーがビューをスクロールした場合は、別のツリー ノードが先頭になる場合があります。

メモ
Scrollable プロパティ値が false の場合は、このプロパティを設定しても影響はありません。

使用例

BeforeLabelEdit、AfterSelect、および TopNode の各メンバの使用方法を次のコード例に示します。この例を実行するには、TreeView1 という名前の TreeView コントロールが配置されているフォームに、次のコードを貼り付けます。そして、フォームのコンストラクタまたは Load メソッドで InitializeTreeView メソッドを呼び出します。

Visual Basic

    Private Sub InitializeTreeView()

        ' Construct the TreeView object.
        Me.TreeView1 = New System.Windows.Forms.TreeView

        ' Set dock, location, size name, and tab order
        ' values for the TreeView object.

        With TreeView1
            .Dock = System.Windows.Forms.DockStyle.Left
            .Location = New System.Drawing.Point(0, 0)
            .Name = "TreeView1"
            .Size = New System.Drawing.Size(152, 266)
            .TabIndex = 1
        End With

        ' Set the LabelEdit property to true to allow the 
        ' user to edit the TreeNode text.
        Me.TreeView1.LabelEdit = True

        ' Declare and create objects needed to populate 
        ' the TreeView.
        Dim file, files(), filePath As String
        files = New String() {"bigPresentation.ppt",
 "myFinances.xls", _
            "myResume.doc"}
        filePath = "c:\myFiles"
        Dim nodes As New
 System.Collections.ArrayList

        ' Create a node for each file, setting the Text property to
 the 
        ' file's name and the Tag property to file's fully-qualified
 name.
        For Each file In
 files
            Dim node As New
 TreeNode(file)
            node.Tag = filePath & "\" & file
            nodes.Add(node)
        Next

        ' Create a new node named topNode and add the ArrayList of 
        ' nodes to topNode.
        Dim topNode As New
 TreeNode("myFiles", _
            nodes.ToArray(GetType(TreeNode)))

        topNode.Tag = filePath

        ' Add topNode to the TreeView.
        TreeView1.Nodes.Add(topNode)

        ' Add the TreeView to the form.
        Me.Controls.Add(TreeView1)
    End Sub

    Private Sub TreeView1_BeforeLabelEdit(ByVal
 sender As Object, _
        ByVal e As NodeLabelEditEventArgs)
 Handles TreeView1.BeforeLabelEdit

        ' Determine whether the user has selected the top node. If so
,
        ' change the LabelEdit property to false so the user cannot
        ' edit this label.  
        If (e.Node Is TreeView1.TopNode) Then

            TreeView1.LabelEdit = False
            MessageBox.Show("You are not allowed to edit the top
 node")
        End If

        ' Set the LabelEdit property to true again.
        TreeView1.LabelEdit = True
    End Sub
<br /><span space="preserve">...</span><br
 />    ' Handle the After_Select event.
    Private Sub TreeView1_AfterSelect(ByVal
 sender As System.Object, _
        ByVal e As System.Windows.Forms.TreeViewEventArgs)
 _
            Handles TreeView1.AfterSelect

        ' Vary the response depending on which TreeViewAction
        ' triggered the event. 
        Select Case (e.Action)
            Case TreeViewAction.ByKeyboard
                MessageBox.Show("You like the keyboard!")
            Case TreeViewAction.ByMouse
                MessageBox.Show("You like the mouse!")
        End Select
    End Sub

C#

    private void InitializeTreeView()
    {

        // Construct the TreeView object.
        this.TreeView1 = new System.Windows.Forms.TreeView();

        // Set dock, location, size name, and tab order
        // values for the TreeView object.
        TreeView1.Dock = System.Windows.Forms.DockStyle.Left;
        TreeView1.Location = new System.Drawing.Point(0, 0);
        TreeView1.Name = "TreeView1";
        TreeView1.Size = new System.Drawing.Size(152, 266);
        TreeView1.TabIndex = 1;
        
        // Associate the event-handling methods with the
        // BeforeLabeEdit and the AfterSelect events.
        TreeView1.BeforeLabelEdit += 
            new NodeLabelEditEventHandler(TreeView1_BeforeLabelEdit);
        TreeView1.AfterSelect += 
            new TreeViewEventHandler(TreeView1_AfterSelect);

        // Set the LabelEdit property to true to allow the 
        // user to edit the TreeNode text.
        this.TreeView1.LabelEdit = true;

        // Declare and create objects needed to populate 
        // the TreeView.
        string[] files = new string[]{"bigPresentation.ppt",
 
            "myFinances.xls", "myResume.doc"};; 
        string filePath = "c:\\myFiles";
        System.Collections.ArrayList nodes = 
            new System.Collections.ArrayList();

        // Create a node for each file, setting the Text property to
 the 
        // file's name and the Tag property to file's fully-qualified
 name.
        foreach ( string file in
 files )
        {
            TreeNode node = new TreeNode(file);
            node.Tag = filePath+"\\"+file;
            nodes.Add(node);
        }

        TreeNode[] treeNodes = new TreeNode[nodes.Count];
        nodes.CopyTo(treeNodes);

        // Create a new node named topNode and add the ArrayList of
 
        // nodes to topNode.
        TreeNode topNode = new TreeNode("myFiles", 
 treeNodes);
        topNode.Tag = filePath;

        // Add topNode to the TreeView.
        TreeView1.Nodes.Add(topNode);

        // Add the TreeView to the form.
        this.Controls.Add(TreeView1);
    }

    private void TreeView1_BeforeLabelEdit(object
 sender, 
        NodeLabelEditEventArgs e)
    {

        // Determine whether the user has selected the top node. If
 so,
        // change the LabelEdit property to false so the user cannot
        // edit this label.  
        if (e.Node == TreeView1.TopNode)

        {
            TreeView1.LabelEdit = false;
            MessageBox.Show("You are not allowed to edit the top node");
        }
        // Set the LabelEdit property to true again.
        TreeView1.LabelEdit = true;
    }
<br /><span space="preserve">...</span><br /> 
   // Handle the After_Select event.
    private void TreeView1_AfterSelect(System.Object
 sender, 
        System.Windows.Forms.TreeViewEventArgs e)
    {

        // Vary the response depending on which TreeViewAction
        // triggered the event. 
        switch((e.Action))
        {
            case TreeViewAction.ByKeyboard:
                MessageBox.Show("You like the keyboard!");
                break;
            case TreeViewAction.ByMouse:
                MessageBox.Show("You like the mouse!");
                break;
        }
    }

C++

private:
   void InitializeTreeView()
   {
      
      // Construct the TreeView object.
      this->TreeView1 = gcnew System::Windows::Forms::TreeView;
      
      // Set dock, location, size name, and tab order
      // values for the TreeView object.
      TreeView1->Dock = System::Windows::Forms::DockStyle::Left;
      TreeView1->Location = System::Drawing::Point( 0, 0 );
      TreeView1->Name = "TreeView1";
      TreeView1->Size = System::Drawing::Size( 152, 266 );
      TreeView1->TabIndex = 1;
      
      // Associate the event-handling methods with the
      // BeforeLabeEdit and the AfterSelect events.
      TreeView1->BeforeLabelEdit += gcnew NodeLabelEditEventHandler( this,
 &Form1::TreeView1_BeforeLabelEdit );
      TreeView1->AfterSelect += gcnew TreeViewEventHandler( this,
 &Form1::TreeView1_AfterSelect );
      
      // Set the LabelEdit property to true to allow the 
      // user to edit the TreeNode text.
      this->TreeView1->LabelEdit = true;
      
      // Declare and create objects needed to populate 
      // the TreeView.
      array<String^>^files = {"bigPresentation.ppt","myFinances.xls"
,"myResume.doc"};
      ;
      String^ filePath = "c:\\myFiles";
      System::Collections::ArrayList^ nodes = gcnew System::Collections::ArrayList;
      
      // Create a node for each file, setting the Text property to the
 
      // file's name and the Tag property to file's fully-qualified
 name.
      System::Collections::IEnumerator^ myEnum = files->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         String^ file = safe_cast<String^>(myEnum->Current);
         TreeNode^ node = gcnew TreeNode( file );
         node->Tag = String::Concat( filePath, "\\", file );
         nodes->Add( node );
      }

      array<TreeNode^>^treeNodes = gcnew array<TreeNode^>(nodes->Count);
      nodes->CopyTo( treeNodes );
      
      // Create a new node named topNode and add the ArrayList of 
      // nodes to topNode.
      TreeNode^ topNode = gcnew TreeNode( "myFiles",treeNodes );
      topNode->Tag = filePath;
      
      // Add topNode to the TreeView.
      TreeView1->Nodes->Add( topNode );
      
      // Add the TreeView to the form.
      this->Controls->Add( TreeView1 );
   }

   void TreeView1_BeforeLabelEdit( Object^ /*sender*/, NodeLabelEditEventArgs^
 e )
   {
      
      // Determine whether the user has selected the top node. If so
,
      // change the LabelEdit property to false so the user cannot
      // edit this label.  
      if ( e->Node == TreeView1->TopNode )
      {
         TreeView1->LabelEdit = false;
         MessageBox::Show( "You are not allowed to edit the top node" );
      }

      
      // Set the LabelEdit property to true again.
      TreeView1->LabelEdit = true;
   }
<br /><span space="preserve">...</span><br />private:
   // Handle the After_Select event.
   void TreeView1_AfterSelect( System::Object^ /*sender*/, System::Windows::Forms::TreeViewEventArgs^
 e )
   {
      
      // Vary the response depending on which TreeViewAction
      // triggered the event. 
      switch ( (e->Action) )
      {
         case TreeViewAction::ByKeyboard:
            MessageBox::Show( "You like the keyboard!" );
            break;

         case TreeViewAction::ByMouse:
            MessageBox::Show( "You like the mouse!" );
            break;
      }
   }

J#

    private void InitializeTreeView()
    {
        // Construct the TreeView object.
        this.treeView1 = new System.Windows.Forms.TreeView();
        // Set dock, location, size name, and tab order
        // values for the TreeView object.
        treeView1.set_Dock(System.Windows.Forms.DockStyle.Left);
        treeView1.set_Location(new System.Drawing.Point(0, 0));
        treeView1.set_Name("TreeView1");
        treeView1.set_Size(new System.Drawing.Size(152, 266));
        treeView1.set_TabIndex(1);
        // Associate the event-handling methods with the
        // BeforeLabeEdit and the AfterSelect events.
        treeView1.add_BeforeLabelEdit(
            new NodeLabelEditEventHandler(treeView1_BeforeLabelEdit));
        treeView1.add_AfterSelect(new TreeViewEventHandler(
            treeView1_AfterSelect));
        // Set the LabelEdit property to true to allow the 
        // user to edit the TreeNode text.
        this.treeView1.set_LabelEdit(true);
        // Declare and create objects needed to populate 
        // the TreeView.
        String files[] = new String[] { "bigPresentation.ppt",
 "myFinances.xls",
            "myResume.doc" };
        String filePath = "c:\\myFiles";
        System.Collections.ArrayList nodes = new System.Collections.ArrayList();
        // Create a node for each file, setting the Text property to
 the 
        // file's name and the Tag property to file's fully-qualified
 name.
        for (int iCtr = 0; iCtr < files.length;
 iCtr++) {
            String file = files[iCtr];
            TreeNode node = new TreeNode(file);
            node.set_Tag(filePath + "\\" + file);
            nodes.Add(node);
        }

        TreeNode treeNodes[] = new TreeNode[nodes.get_Count()];
        nodes.CopyTo(treeNodes);
        // Create a new node named topNode and add the ArrayList of
 
        // nodes to topNode.
        TreeNode topNode = new TreeNode("myFiles", treeNodes);
        topNode.set_Tag(filePath);
        // Add topNode to the TreeView.
        treeView1.get_Nodes().Add(topNode);
        // Add the TreeView to the form.
        this.get_Controls().Add(treeView1);
    } //InitializeTreeView

    private void treeView1_BeforeLabelEdit(Object
 sender,
        NodeLabelEditEventArgs e)
    {
        // Determine whether the user has selected the top node. If
 so,
        // change the LabelEdit property to false so the user cannot
        // edit this label.  
        if (e.get_Node().Equals(treeView1.get_TopNode())) {
            treeView1.set_LabelEdit(false);
            MessageBox.Show("You are not allowed to edit the top node");
        }
        // Set the LabelEdit property to true again.
        treeView1.set_LabelEdit(true);
    } //treeView1_BeforeLabelEdit
<br /><span space="preserve">...</span><br /> 
   // Handle the After_Select event.
    private void treeView1_AfterSelect(Object
 sender,
        System.Windows.Forms.TreeViewEventArgs e)
    {
        // Vary the response depending on which TreeViewAction
        // triggered the event. 
        switch (e.get_Action()) {
            case TreeViewAction.ByKeyboard:
                MessageBox.Show("You like the keyboard!");
                break;
            case TreeViewAction.ByMouse:
                MessageBox.Show("You like the mouse!");
                break;
        }
    } //treeView1_AfterSelect

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0

参照

関連項目
TreeView クラス
TreeView メンバ
System.Windows.Forms 名前空間
TreeNode.IsVisible プロパティ