How can I cancel a user's WPF TreeView click?

Question

I\'ve got a WPF application with a Treeview control.

When the user clicks a node on the tree, other TextBox, ComboBox, etc. controls on the page are populated with a

Answer 1

You could create your custom control that derives from TreeView and then override the OnSelectedItemChanged method.

Before calling the base, you could first fire a custom event with a CancelEventArgs parameter. If the parameter.Cancel become true, then don't call the base, but select the old item instead (be careful that the OnSelectedItemChanged will be called again).

Not the best solution, but at least this keeps the logic inside the tree control, and there is not chance that the selection change event fires more than it's needed. Also, you don't need to care if the user clicked the tree, used the keyboard or maybe the selection changed programatically.

Answer 2

CAMS_ARIES:

XAML:

code :

  private bool ManejarSeleccionNodoArbol(Object origen)
    {
        return true;  // with true, the selected nodo don't change
        return false // with false, the selected nodo change
    }


    private void Arbol_PreviewMouseDown(object sender, MouseButtonEventArgs e)
    {            
        if (e.Source is TreeViewItem)
        {
            e.Handled = ManejarSeleccionNodoArbol(e.Source);
        }
    }

    private void Arbol_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        if (e.Source is TreeViewItem)
        {
           e.Handled=ManejarSeleccionNodoArbol(e.Source);
        }
    }         

Answer 3

Since the SelectedItemChanged event is triggered after the SelectedItem has already changed, you can't really cancel the event at this point.

What you can do is listen for mouse-clicks and cancel them before the SelectedItem gets changed.