无法将流复制到文件

Question

我必须从 SpeechSynthesizer 生成的流中创建一个音频文件。

这是我正在使用的代码

var stream = await _SpeechSynth.GetSpeakStreamAsync(text, this.Language);
            var reader = new Windows.Storage.Streams.DataReader(stream.GetInputStreamAt(0));
            await reader.LoadAsync((uint)stream.Size);

            byte[] bytes = new byte[stream.Size];
            reader.ReadBytes(bytes);

             var audioFile = await ApplicationData.Current.TemporaryFolder.CreateFileAsync(_AgendaAudioFilename, CreationCollisionOption.ReplaceExisting);

             using (var outputStream = await audioFile.OpenAsync(FileAccessMode.ReadWrite))
             {

                 Stream os = outputStream.GetOutputStreamAt(0).AsStreamForWrite();
                 await os.WriteAsync(bytes, 0, bytes.Length);
             }

我发现问题在于“os.WriteAsync”没有被等待。当我在该行放置断点并等待几秒钟时，文件正在正确创建。 await 关键字不应该等到所有字节都复制到流中再转到下一行吗？

我不介意是否有人可以建议将 InMemoryRandomAccessStream 复制到文件的更好方法？

编辑：

Mahantesh 的回答很有魅力。非常感谢。但我面临一个新问题。

创建文件后，我试图再次打开它以播放它，但出现此错误。

“访问被拒绝。（来自 HRESULT 的异常：0x80070005 (E_ACCESSDENIED)）”

这是我的代码。

if (!cacheHit)
        {
            var stream = await _SpeechSynth.GetSpeakStreamAsync(text, this.Language);

            //write the stream to disk (seems to be buggy when attempting to playback from the result of the speech synth request)
            var audioFile = await ApplicationData.Current.TemporaryFolder.CreateFileAsync(_AgendaAudioFilename, CreationCollisionOption.ReplaceExisting);

             outputStream = await audioFile.OpenAsync(FileAccessMode.ReadWrite);

             await RandomAccessStream.CopyAsync(stream, outputStream);                 

        }

        //read agenda from disk and play back the audio
        var agendaStorageFile = await ApplicationData.Current.TemporaryFolder.GetFileAsync(_AgendaAudioFilename);
        var agendaStreamFromDisk = await agendaStorageFile.OpenAsync(FileAccessMode.Read);            

        _MediaPlayer.Url = text;
        _MediaPlayer.SetBytestream(agendaStreamFromDisk);
        _MediaPlayer.Play();    

我在这一行得到错误：

var agendaStreamFromDisk = await agendaStorageFile.OpenAsync(FileAccessMode.Read);

知道可能出了什么问题吗？

Answer 1

我觉得你可以试试

await RandomAccessStream.CopyAsync(inMemoryStream, outputStream);

新问题的解决方案：

if (!cacheHit)
    {
        var stream = await _SpeechSynth.GetSpeakStreamAsync(text, this.Language);

        //write the stream to disk (seems to be buggy when attempting to playback from the result of the speech synth request)
        var audioFile = await ApplicationData.Current.TemporaryFolder.CreateFileAsync(_AgendaAudioFilename, CreationCollisionOption.ReplaceExisting);

         using(outputStream = await audioFile.OpenAsync(FileAccessMode.ReadWrite)){
         await RandomAccessStream.CopyAsync(stream, outputStream);}

    }

    //read agenda from disk and play back the audio
    var agendaStorageFile = await ApplicationData.Current.TemporaryFolder.GetFileAsync(_AgendaAudioFilename);
   using (var agendaStreamFromDisk = await agendaStorageFile.OpenAsync(FileAccessMode.Read)){

    _MediaPlayer.Url = text;
    _MediaPlayer.SetBytestream(agendaStreamFromDisk);
    _MediaPlayer.Play();  }

Answer 2

当您使用 await 关键字等待时，最好使用同步版本的方法，例如

using (var outputStream = audioFile.Open(FileAccessMode.ReadWrite))
{
    Stream os = outputStream.GetOutputStreamAt(0).AsStreamForWrite();
    os.Write(bytes, 0, bytes.Length);
}