Export (0) Print
Expand All

TreeView.LabelEdit Property

Gets or sets a value indicating whether the label text of the tree nodes can be edited.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public bool LabelEdit { get; set; }

Property Value

Type: System.Boolean
true if the label text of the tree nodes can be edited; otherwise, false. The default is false.

The BeginEdit method works only if the LabelEdit property is true. If LabelEdit is false when you attempt to edit the label, an exception will be thrown and the tree node will not be put in to an editable state.

The following code example lets the user edit nonroot tree nodes by using a ContextMenu. When the user right clicks the mouse, the TreeNode at that position is determined and stored in a variable named mySelectedNode. If a nonroot tree node was selected, it is put into an editable state, which allows the user to edit the node label. After the user stops editing the tree node label, the new label text is evaluated and saved. For this example, several characters are considered not valid in the label text. If one of the invalid characters is in the label string, or the string is empty, the user is notified of the error and the label is returned to its previous text.


/* Get the tree node under the mouse pointer and 
   save it in the mySelectedNode variable. */
private void treeView1_MouseDown(object sender, 
  System.Windows.Forms.MouseEventArgs e)
{
   mySelectedNode = treeView1.GetNodeAt(e.X, e.Y);
}

private void menuItem1_Click(object sender, System.EventArgs e)
{
   if (mySelectedNode != null && mySelectedNode.Parent != null)
   {
      treeView1.SelectedNode = mySelectedNode;
      treeView1.LabelEdit = true;
      if(!mySelectedNode.IsEditing)
      {
         mySelectedNode.BeginEdit();
      }
   }
   else
   {
      MessageBox.Show("No tree node selected or selected node is a root node.\n" + 
         "Editing of root nodes is not allowed.", "Invalid selection");
   }
}

private void treeView1_AfterLabelEdit(object sender, 
         System.Windows.Forms.NodeLabelEditEventArgs e)
{
   if (e.Label != null)
   {
     if(e.Label.Length > 0)
     {
        if (e.Label.IndexOfAny(new char[]{'@', '.', ',', '!'}) == -1)
        {
           // Stop editing without canceling the label change.
           e.Node.EndEdit(false);
        }
        else
        {
           /* Cancel the label edit action, inform the user, and 
              place the node in edit mode again. */
           e.CancelEdit = true;
           MessageBox.Show("Invalid tree node label.\n" + 
              "The invalid characters are: '@','.', ',', '!'", 
              "Node Label Edit");
           e.Node.BeginEdit();
        }
     }
     else
     {
        /* Cancel the label edit action, inform the user, and 
           place the node in edit mode again. */
        e.CancelEdit = true;
        MessageBox.Show("Invalid tree node label.\nThe label cannot be blank", 
           "Node Label Edit");
        e.Node.BeginEdit();
     }
   }
}


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Community Additions

ADD
Show:
© 2014 Microsoft