C# 正在读取guide.beginshowmessagebox的结果

目前，当我的XNA游戏启动时，当用户通过媒体播放器播放音乐时，我会弹出一个消息框。它有两个按钮，是和否。我需要做的是确定用户按下了哪个按钮，这样我就可以使用IF语句根据结果执行相关操作。目前我的代码是：

    Public Sub playmusic()
    FrameworkDispatcher.Update()
    If MediaPlayer.GameHasControl = False Then

        'Add everything below when you want to show the message box
        Dim MBOPTIONS As New List(Of String)()
        MBOPTIONS.Add("Yes")
        MBOPTIONS.Add("No")
        Dim result As IAsyncResult = Guide.BeginShowMessageBox("Music request", "Do you want to stop your music and play the in-game music?", MBOPTIONS, 0, MessageBoxIcon.Alert, Nothing, Nothing)

        result.AsyncWaitHandle.WaitOne()


        Dim choice As System.Nullable(Of Integer) = Guide.EndShowMessageBox(result)

        If choice.HasValue Then
            If choice.Value = 0 Then
                MediaPlayer.Stop()
                sounds = True


            Else

                sounds = False

            End If
        End If



    End If






End Sub

有人能帮我读结果需要什么代码吗