更改FileSavePicker以将文件从隔离存储而不是应用程序存储保存。异常WP8.1

Question

更新我的代码在我的SoundData与var ...线。我实际上只是看到文件夹保存到现在，但我试图挑选一个文件夹并保存时遇到异常。

+ $ exception {System.IO.FileNotFoundException：系统找不到指定的文件。

这里app.xaml.cs：

IStorageFile的SourceFile =等待folder.GetFileAsync（sourceFilePath）;

App.xaml.cs：

private async void Application_ContractActivated(object sender, Windows.ApplicationModel.Activation.IActivatedEventArgs e) 
    { 
     var args = e as FileSavePickerContinuationEventArgs; 
     if (args != null) 
     { 
      StorageFile file = args.File; 
      if (file != null) 
      { 
       // Prevent updates to the remote version of the file until we finish making changes and call CompleteUpdatesAsync. 
       CachedFileManager.DeferUpdates(file); 
       // write to file 
       var sourceFilePath = args.ContinuationData["SourceSound"].ToString(); 
       StorageFolder folder = Windows.ApplicationModel.Package.Current.InstalledLocation; 
       StorageFile sourceFile = await folder.GetFileAsync(sourceFilePath); 

       IRandomAccessStreamWithContentType sourceStream = await sourceFile.OpenReadAsync(); 

      var bytes = new byte[sourceStream.Size]; 

      var sourceBuffer = await sourceStream.ReadAsync(bytes.AsBuffer(), (uint)sourceStream.Size, Windows.Storage.Streams.InputStreamOptions.None); 

       await FileIO.WriteBufferAsync(file, sourceBuffer); 
       // Let Windows know that we're finished changing the file so the other app can update the remote version of the file. 
       // Completing updates may require Windows to ask for user input. 
       FileUpdateStatus status = await CachedFileManager.CompleteUpdatesAsync(file); 
      } 
     } 
    } 

SoundData视图模型：

private async void ExecuteSaveSoundAs(string soundPath) 
    { 

     var file = await ApplicationData.Current.LocalFolder.GetFileAsync(SavePath); 

     FileSavePicker savePicker = new FileSavePicker(); 
     savePicker.SuggestedSaveFile = file; 
     savePicker.FileTypeChoices.Add("MP3", new List<string>() { ".mp3" }); 
     savePicker.ContinuationData.Add("SourceSound", SavePath); 
     savePicker.SuggestedFileName = this.Title; 
     savePicker.PickSaveFileAndContinue(); 
    } 


    public SoundData() 
    { 
     SaveSoundAs = new RelayCommand<string>(ExecuteSaveSoundAs);    
    } 

SoundModel：

private SoundGroup CreateSoftwareGroup() 
    { 
     SoundGroup data = new SoundGroup(); 

     data.Title = "OS/Software"; 

     data.Items.Add(new SoundData 
     { 
      Title = "Test1", 
      FilePath = "https://xxxxx.test1.mp3", 
      Groups = "Test", 
      SavePath = "Test1.mp3" 
     }); 

     data.Items.Add(new SoundData 
     { 
      Title = "Test2", 
      FilePath = "https://xxxxx.Test2.mp3", 
      Groups = "Test", 
      SavePath = "Test2.mp3" 
     }); 

Answer 1

下面是解：

代码在网主页。 C S修饰：

var sourceFilePath = args.ContinuationData["SourceSound"].ToString(); 
       StorageFolder folder = ApplicationData.Current.LocalFolder; 
       StorageFile sourceFile = await folder.GetFileAsync(sourceFilePath); 

而且我FileSavePicker代码：

private async void ExecuteSaveSoundAs(string soundPath) 
    { 

     var file = await ApplicationData.Current.LocalFolder.GetFileAsync(SavePath); 

     FileSavePicker savePicker = new FileSavePicker(); 
     savePicker.SuggestedSaveFile = file; 
     savePicker.FileTypeChoices.Add("MP3", new List<string>() { ".mp3" }); 
     savePicker.ContinuationData.Add("SourceSound", SavePath); 
     savePicker.SuggestedFileName = this.Title; 
     savePicker.PickSaveFileAndContinue(); 
    }