Occurs when the CommandManager detects conditions that might change the ability of a command to execute.
public static event EventHandler RequerySuggested;
Since this event is static, it will only hold onto the handler as a weak reference. Objects that listen for this event should keep a strong reference to their event handler to avoid it being garbage collected. This can be accomplished by having a private field and assigning the handler as the value before or after attaching to this event.