WinrtXamlToolkit TreeView expand with single instead of double click

Question

I am using the TreeView from the WinrtXamlToolkit. The default behavior of this control is to expand the nested items on double click of the header. The code responsible for this is here (TreeViewItem.cs line 1205).

private void OnHeaderMouseLeftButtonDown(object sender, PointerRoutedEventArgs e)
        {
            if (Interaction.AllowMouseLeftButtonDown(e))
            {
                // If the event hasn't already been handled and this item is
                // focusable, then focus (and possibly expand if it was double
                // clicked)
                if (!e.Handled && IsEnabled)
                {
                    if (Focus(FocusState.Programmatic))
                    {
                        e.Handled = true;
                    }

                    // Expand the item when double clicked
                    if (Interaction.ClickCount % 2 == 0)
                    {
                        bool opened = !IsExpanded;
                        UserInitiatedExpansion |= opened;
                        IsExpanded = opened;

                        e.Handled = true;
                    }
                }

                Interaction.OnMouseLeftButtonDownBase();
                OnPointerPressed(e);
            }
        }

Is there a way to change this behavior to expand the items on single click or tap without actually copying the control and all it's related classes to my project?

It seems like an overkill to do this just to change a few lines of code.

Answer 1

I tried to do drag'n'drop stuff with that TreeView and was in a similar situation. My first move was to actually copy all the TreeView and its related classes and man there are a lot. There's a lot of internal stuff happening and I pretty much gave up interfering with it after a bunch of other stuff stopped working.

So my solution was to just have a specific control inside the ItemTemplate that handled dragging for me. For you this would be a Button whose Click you handle. In the eventhandler you will navigate up the visual tree to your TreeViewItem and change the IsExpanded.