尽管线程同步C,但仍发生IOException#

我在同一个类中声明了两个事件处理程序(我们称之为 WrapperClass ):一个用于将文件保存到文件夹,另一个用于将这些文件发送到web api。在应用程序主线程中,我在应用程序启动时调用了两种方法:

// save file to folder:
NewFileEventHandler();
// send file to api:
FileTransporter();

NewFileEventHandler 定义如下:

public void NewFileEventHandler()
{
    SomeEventClass.NewFileEvent +=
         new FileEventHandler(SaveFileToFolder);
}

private void SaveFileToFolder(File file)
{
    FileHelper.SaveFileToFolder(file);
}

FileTransporter 定义如下,这就是我的问题所在:

public void FileTransporter()
{
     FileSystemWatcher newFileWatcher = new FileSystemWatcher();
     newFileWatcher.Path = ConfigurationHelper.applicationRootDirectory;
     newFileWatcher.Filter = "*.txt";
     newFileWatcher.Created +=
     new FileSystemEventHandler(TransportFile);
     newFileWatcher.EnableRaisingEvents = true;
}

And the `TransportFile()` is given below:

private void TransportFile(object source, FileSystemEventArgs e)
{
    lock (_fileTransportLock)
    {
         string[] files = new string[] { };
         files = Directory.GetFiles(ConfigurationHelper.applicationRootDirectory, "*.txt", SearchOption.TopDirectoryOnly);
         Parallel.ForEach(files, (currentFile) =>
         {
             bool isHttpTransferSuccess = false;

             isHttpTransferSuccess = FileHelper.SendFileToApi(userid, currentFile);
             if (isHttpTransferSuccess)
             {
                 File.Delete(currentFile);
             }
        });
     }
}

但是,该行:

引发异常:

System.IO.IOException: The process cannot access the file 'C:\Users\myapp\file.txt' because it is being used by another process.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
   at System.IO.File.Open(String path, FileMode mode)
   at FileHelper.SendFileToApi(String userId, String fileLocation)

我不明白的是,因为 lock 唯一可能使用此文件的两个进程是保存文件的线程和尝试将文件发送到api的线程。然而,我对 FileSystemWatcher.Created 事件是指它在文件创建完成时触发。也就是说,保存文件的线程在 TransportFile() 方法尝试打开文件以将其发送到api。

有时文件夹中有多个文件(由于过去丢失了电子邮件)。这个 IOException 仅针对刚刚保存到文件夹的文件(换句话说,引发 FileSystemWatcher。创建 事件按预期清除文件夹中的其他文件。有人能帮忙吗?谢谢