问如何停止调用OnBackKeyPress方法按下wp8中的硬件回键？

EN

class EventTesterClass // Simple class that raise an event
{
    public event EventHandler Func;

    public void RaiseEvent()
    {
        Func(null, EventArgs.Empty);
    }
}

static void subscribeEventBeforeOthers<InstanceType>(InstanceType instance, string eventName, EventHandler handler) // Magic method that unsubscribe subscribed methods, subscribe the new method and resubscribe previous methods
{
    Type instanceType = typeof(InstanceType);
    var eventInfo = instanceType.GetEvent(eventName);
    var eventFieldInfo = instanceType.GetField(eventInfo.Name,
                                        BindingFlags.NonPublic |
                                        BindingFlags.Instance |
                                        BindingFlags.GetField);

    var eventFieldValue = (System.Delegate)eventFieldInfo.GetValue(instance);
    var methods = eventFieldValue.GetInvocationList();

    foreach (var item in methods)
    {
        eventInfo.RemoveEventHandler(instance, item);
    }
    eventInfo.AddEventHandler(instance, handler);
    foreach (var item in methods)
    {
        eventInfo.AddEventHandler(instance, item);
    }
}

static void Main(string[] args)
{
    var evntTest = new EventTesterClass();
    evntTest.Func += handler_Func;
    evntTest.Func += handler_Func1;
    evntTest.RaiseEvent();
    Console.WriteLine();
    subscribeEventBeforeOthers(evntTest, "Func", handler_Func2);
    evntTest.RaiseEvent();
}

static void handler_Func(object sender, EventArgs e)
{
    Console.WriteLine("handler_Func");
}

static void handler_Func1(object sender, EventArgs e)
{
    Console.WriteLine("handler_Func1");
}

static void handler_Func2(object sender, EventArgs e)
{
    Console.WriteLine("handler_Func2");
}

handler_Func
handler_Func1

handler_Func2
handler_Func
handler_Func1