WCF Streaming - 谁关闭文件？

Question

根据 Microsoft 的示例，以下是通过 WCF 流式传输文件的方法:

   // 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，我怎么知道在传输完成后谁负责释放 FileStream？

编辑:如果将代码放在“使用”块中，则在客户端收到任何内容之前，流将关闭。

Answer 1

服务应该清理而不是客户端。 WCF 的 OperationBehaviorAttribute.AutoDisposeParameters 的默认值似乎是 true，因此它应该为您进行处理。尽管对此似乎没有固定的答案。

您可以尝试使用 OperationContext.OperationCompleted Event :

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

把它放在你回来之前。

检查这个 blog