C# 为什么分派器委托在WinRT中工作？

下面的代码适用于Windows Phone 7

    private void ShowTime()
    {
        txtTime.Text = get24hour();

        //display the Date and week.
        DateTime nowtime = DateTime.Now;
        txtWeek.Text = nowtime.DayOfWeek.ToString();
        txtDate.Text = nowtime.Date.ToString("MM/dd");   

        //create timer to fresh to time
        DispatcherTimer timer = new DispatcherTimer();
        timer.Interval = TimeSpan.FromMinutes(1);
        timer.Tick += timer_Ticker;
        timer.Start();        
    }

    private void timer_Ticker(object sender, EventArgs e)
    {
        txtTime.Text = get24hour();
    }

    private string get24hour()
    {
        return DateTime.Now.ToString("HH:mm");
    }

但WinRT（Metro）中出现错误

错误部分：

  timer.Tick += timer_Ticker;

错误消息：

  No overload for 'timer_Ticker' matches delegate 'System.EventHandler<object>' 

结果

---

但它又不起作用了，为什么以及如何解决它（

我阅读了msdn，并将委托方法更改为下面的方法，它可以工作：

    private void timer_Ticker(object sender, object e)
    {
        txtTime.Text = get24hour();
    }

timer.Tick+=新的事件处理程序（timer\u Tick）；
私有无效计时器（对象发送方，对象e）
{
}

指

    private void timer_Ticker(object sender, object e)
    {
        txtTime.Text = get24hour();
    }

timer.Tick += new EventHandler<object>(timer_Tick); 

private void timer_Tick(object sender, object e)
{
}