WPF:为什么 PopUp 中的 MediaElement 不能调整到屏幕高度？

Question

我在 PopUp 中有 MediaElement 控件。当我将 MediaElement 调整为宽屏时，它会在底部切出一个区域(参见图片)。

我做错了什么？如何解决？非常感谢!

XAML:

    <Popup PlacementRectangle="-500,0,0,0" Placement="Relative" IsOpen="True" Name="popup">
        <MediaElement Name="me" Width="480" Height="360" Volume="1"
            MouseLeftButtonUp="me_MouseLeftButtonUp"/>
    </Popup>

代码:

    bool fullscreen = false;
    private void me_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
    {
        fullscreen = !fullscreen;
        if (fullscreen)
        {
            popup.PlacementRectangle = new Rect(0, 0, 0, 0);
            popup.Placement = PlacementMode.Absolute;
            me.Width = Screen.PrimaryScreen.Bounds.Width;
            me.Height = Screen.PrimaryScreen.Bounds.Height;
        }
        else
        {
            popup.PlacementRectangle = new Rect(-500, 0, 0, 0);
            popup.Placement = PlacementMode.Relative;
            me.Width = 480;
            me.Height = 360;
        }
    }

Answer 1

弹出窗口不能覆盖超过 75% 的屏幕。

请参阅此线程:Can't create a fullscreen WPF popup