WCF Streaming - 谁关闭文件？

Question

根据微软的样本,以下是如何通过WCF流​​式传输文件:

   // Service class which implements the service contract
    public class StreamingService : IStreamingSample
    {

        public System.IO.Stream GetStream(string data)
        {
            //this file path assumes the image is in
            // the Service folder and the service is executing
            // in service/bin 
            string filePath = Path.Combine(
                System.Environment.CurrentDirectory,
                ".\\image.jpg");
            //open the file, this could throw an exception 
            //(e.g. if the file is not found)
            //having includeExceptionDetailInFaults="True" in config 
            // would cause this exception to be returned to the client
            try
            {
                FileStream imageFile = File.OpenRead(filePath);
                return imageFile;
            }
            catch (IOException ex)
            {
                Console.WriteLine(
                    String.Format("An exception was thrown while trying to open file {0}", filePath));
                Console.WriteLine("Exception is: ");
                Console.WriteLine(ex.ToString());
                throw ex;
            }
        }
...

现在,我怎么知道谁在转移完成后负责释放FileStream？

编辑:如果代码放在"使用"块中,流将在客户端收到任何内容之前关闭.

Answer 1

该服务应该清理而不是客户端.对于OperationBehaviorAttribute.AutoDisposeParameters,WCF的默认值似乎是正确的,因此它应该为您进行处理.虽然似乎没有一个固定的答案.

您可以尝试使用OperationContext.OperationCompleted事件:

OperationContext clientContext = OperationContext.Current;
clientContext.OperationCompleted += new EventHandler(delegate(object sender, EventArgs args)
   {
      if (fileStream != null)
         fileStream.Dispose();
   });

在你回来之前把它.

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