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TreeView.BeforeLabelEdit Événement

Définition

Se produit avant que le texte de l'étiquette du nœud d'arborescence soit modifié.

C#
public event System.Windows.Forms.NodeLabelEditEventHandler BeforeLabelEdit;
C#
public event System.Windows.Forms.NodeLabelEditEventHandler? BeforeLabelEdit;

Type d'événement

Exemples

L’exemple de code suivant montre comment utiliser les BeforeLabelEditAfterSelect membres et TopNode . Pour exécuter cet exemple, collez le code suivant dans un formulaire qui contient un TreeView contrôle nommé TreeView1. Appelez la InitializeTreeView méthode dans le constructeur ou Load la méthode du formulaire.

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 CancelEdit property to true to cancel the edit.  
    if (e.Node == TreeView1.TopNode)

    {
        e.CancelEdit = true;
        MessageBox.Show("You are not allowed to edit the top node");
    }
}
C#
// 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;
    }
}

Remarques

Pour plus d’informations sur la façon de gérer les événements, consultez gestion et déclenchement d’événements.

S’applique à

Produit Versions
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
Windows Desktop 3.0, 3.1, 5, 6, 7, 8, 9, 10

Voir aussi