How to validate text entered for a new node label in WinForms TreeViewAdv?

private void treeViewAdv1_NodeEditorValidating(object sender, Syncfusion.Windows.Forms.Tools.TreeNodeAdvCancelableEditEventArgs e)
{
   if(e.Label.Length == 0)
   {
      //Cancel the label edit action, inform the user, and place the node in edit mode again.
      e.Cancel = true;
      MessageBox.Show("The label cannot be blank", "Node Label Edit");
      //To end editing mode,call:
      e.ContinueEditing = false;
   }
}

Private Sub treeViewAdv1_NodeEditorValidating(ByVal sender As Object, ByVal e As Syncfusion.Windows.Forms.Tools.TreeNodeAdvCancelableEditEventArgs)
   If e.Label.Length = 0 Then
      ' Cancel the label edit action, inform the user, and place the node in edit mode again.
      e.Cancel = True
      MessageBox.Show("The label cannot be blank", "Node Label Edit")
      ' To end editing mode,call:
      e.ContinueEditing = false;
   End If
End Sub