Default Actions

A default action occurs when an item is double-tapped or Enter is pressed. This action can be fully customized to execute custom logic.

Built-In Default Actions

The only built-in default action is for expandable items to toggle their expansion state. You can cancel this default action by handling the TreeListBox.ItemDefaultActionExecuting event and setting the event args' Cancel property to true.

Customizing Default Actions

In addition to blocking a default action from occurring as above, the TreeListBox.ItemDefaultActionExecuting event can be used for notifications of when to execute a custom action. For instance, when including check boxes on items, you might want to toggle the checked state of the item. Take whatever custom action you wish to take in response to that event. The event is passed arguments of type TreeListBoxItemEventArgs, which specifies the related Item and its UI Container.

If the ItemDefaultActionExecuting event doesn't cancel the default action, then the control will look to see if a TreeListBoxItem.DefaultActionCommand exists. If so, it will try to execute that command.

The TreeListBoxItem.DefaultActionCommand can be set in a TreeListBox.PrepareContainerForItemOverride override. It alternatively can be set via Setter binding in a TreeListBox.ItemContainerStyle style.

Otherwise, the built-in default action will execute, if appropriate.