MessageDialog

 var messageDialog = new Windows.UI.Popups.MessageDialog("Media player components unavailable");
                        await messageDialog.ShowAsync();

或者

using Windows.UI.Popups;

var messageDialog = new MessageDialog("Media player speech text");
            await messageDialog.ShowAsync();

MessageDialog

原文：http://www.cnblogs.com/ansen312/p/5925611.html