Question

我在使用后台传输下载文件时遇到问题。在移动文件后完成下载后，它会为您提供例外Operation not permitted

void addTransferRequest(string fileName)
{
     if (string.IsNullOrEmpty(fileName))
           return;
     string filePathToDownload = string.Empty;
     filePathToDownload = activeReciter.DownloadURL;
     filePathToDownload += fileName;

     Uri transferUri = new Uri(Uri.EscapeUriString(filePathToDownload), 
                               UriKind.RelativeOrAbsolute);
     BackgroundTransferRequest transferRequest = new 
     BackgroundTransferRequest(transferUri);
     transferRequest.Method = "GET";
     transferRequest.TransferPreferences = TransferPreferences.AllowBattery;

     Uri downloadUri = new Uri(DataSource.TEMPDOWNLOADLOCATION + fileName, 
                               UriKind.RelativeOrAbsolute);
     transferRequest.DownloadLocation = downloadUri;
     transferRequest.Tag = fileName;

     transferRequest.TransferStatusChanged += 
       new EventHandler<BackgroundTransferEventArgs>
                                              (transfer_TransferStatusChanged);
     transferRequest.TransferProgressChanged += new 
     EventHandler<BackgroundTransferEventArgs>(transfer_TransferProgressChanged);

     try
     {
       BackgroundTransferService.Add(transferRequest);
       chapterFileNames.Dequeue();
     }
     catch (InvalidOperationException)
     {
     }
     catch (Exception)
     {
     }
}
void transfer_TransferStatusChanged(object sender, BackgroundTransferEventArgs e)
{
   ProcessTransfer(e.Request);
}
void transfer_TransferProgressChanged(object sender, BackgroundTransferEventArgs e)
{
}
private void ProcessTransfer(BackgroundTransferRequest transfer)
{
    switch (transfer.TransferStatus)
    {
       case TransferStatus.Completed:
       if (transfer.StatusCode == 200 || transfer.StatusCode == 206)
       {
             using (IsolatedStorageFile isoStore = 
                    IsolatedStorageFile.GetUserStoreForApplication())
                 {
                   try
                   {
                      string filename = transfer.Tag;
                      string folderPath = string.Format(@"{0}{1}\{2}\", 
                        DataSource.DOWNLOADLOCATION, activeReciter.ReciterID, chapter.ChapterID);
                      string fileFullPath = folderPath + filename;

                      if (!isoStore.DirectoryExists(Path.GetDirectoryName(folderPath)))
                          isoStore.CreateDirectory(Path.GetDirectoryName(folderPath));

                      if (isoStore.FileExists(fileFullPath))
                          isoStore.DeleteFile(fileFullPath);

                      isoStore.MoveFile(transfer.DownloadLocation.OriginalString, fileFullPath); 
                      //Excpetion is thrown here
                      RemoveTransferRequest(transfer.RequestId);
                }
                catch (Exception ex)
                {
                MessageBox.Show("Error Occured: " + ex.Message + transfer.Tag, "Error", 
                                 MessageBoxButton.OK);
                return;
                }
            }
        }
        break;
    }
}

移动文件时，会抛出异常，我不知道移动有什么问题（这种情况发生在某些文件而不是所有文件上）。

Answer 1

MSDN Page下的File System Restrictions部分：

您可以创建您选择的任何其他目录结构在根“/ shared / transfers”目录下，你可以复制或传输完成后移动文件以确保后台传输服务不会修改文件，而是尝试使用“/ shared / transfers”之外的路径启动传输目录将抛出异常。

确保您没有尝试将文件移出/Shared/Transfers文件夹。

BackgroundTransfer无法移动文件

1 个答案: