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我有一个代码将 XML 文件发送到 UdpSocket 并收到答案。我发送和接收异步答案。我的问题是，当我收到来自 UDP 套接字的答案时，我无法将其保存到正确的文件中。我尝试了很多东西，但没有任何效果。

简短地解释我的代码。我开始在 Main() 方法中创建 3 AsynchronousConnection。从那里调用 static void AsynchronousConnection(object objectFilename) 我调用 UdpStartClient 方法。

从 UdpStartClient 方法我发送一个文件 UdpSendXmlFile(fileToSend, udpClient, bytes, CallDuration, out threadId);

之后，我使用方法 UdpReceivedXmlFile("c:\Received" + filename, udpClient, remoteEPReceived, CallDuration, out threadId); 在 while 循环中收到了答案。

我在 UdpReceivedXmlFile 方法中收到的答案将保存到文件中。我想，我的问题就在这里。我通过 AsynchronousConnection 发送 3 个文件并从 UDP 套接字接收到 3 个答案，但答案与我发送的文件不匹配。

例如，我发送这 3 个文件。

消息文本4000.xml

消息文本4001.xml

消息文本8.xml

我随机收到了答案，例如：

文件 MessagingText4000.xml 可以从 MessagingText8.xml 得到答案

文件 MessagingText4001.xml 可以从 MessagingText4000.xml 得到答案

文件 MessagingText8.xml 可以从 MessagingText4001.xml 得到答案

你能帮我，所以我收到了正确文件的正确答案吗？

public delegate void AsyncMethodCall(object objectFilename, int callDuration, out int threadId, out string receivedXmlDataFromTNX);

// Program
public static void Main(String[] args)
{
  Thread newThread;
  newThread = new Thread(AsynchronousConnection);
  newThread.Name = "4001";
  newThread.Start("MessagingText4001.xml");

  newThread = new Thread(AsynchronousConnection);
  newThread.Name = "4000";
  newThread.Start("MessagingText4000.xml");

  newThread = new Thread(AsynchronousConnection);
  newThread.Name = "8";
  newThread.Start("MessagingText8.xml");
}


// Asynchronous Connection 
static void AsynchronousConnection(object objectFilename)
{
  int threadId; string receivedXmlData;
  UdpClass udpClass = new UdpClass();
  AsyncMethodCall caller = new AsyncMethodCall(udpClass.UdpStartClient);
  IAsyncResult result = caller.BeginInvoke(objectFilename, 500, out threadId, out receivedXmlData, null, null);
  result.AsyncWaitHandle.WaitOne();
  caller.EndInvoke(out threadId, out receivedXmlData, result);
  result.AsyncWaitHandle.Close();
}


// UdpClient received 
void UdpReceivedXmlFile(object objectFilename, UdpClient udpClient, IPEndPoint remoteEPReceived, int CallDuration, out int threadId)
{
  Thread.Sleep(CallDuration);
  threadId = Thread.CurrentThread.ManagedThreadId;
  try
  {
    // Blocks until a message returns on this socket from a remote host. 
    Byte[] receiveBytes = udpClient.Receive(ref remoteEPReceived);
    File.WriteAllText((string)objectFilename, Encoding.UTF8.GetString(receiveBytes));
  }
  catch (Exception ex)
  {
    Console.WriteLine("Contact webmaster with this error in UdpReceivedXmlFile:\n " + ex.ToString());
  }
}


// UdpClient send 
void UdpSendXmlFile(string fileToSend, UdpClient udpClient, byte[] bytes, int CallDuration, out int threadId)
{
  Thread.Sleep(CallDuration);
  threadId = Thread.CurrentThread.ManagedThreadId;
  try
  {
    // Encode the data string into a byte array 
    XmlDocument xmlDoc = new XmlDocument();
    xmlDoc.Load(fileToSend);
    // Load XML fil
    string xmlContent = xmlDoc.OuterXml;
    byte[] msg = Encoding.UTF8.GetBytes(xmlDoc.OuterXml);
    // Send the data through the socket.
    udpClient.Send(msg, msg.Length);
  }
  catch (Exception ex)
  { Console.WriteLine("Contact webmaster with this error in UdpSendXmlFile:\n " + ex.ToString()); 
  }
}


// UdpStart Client
public void UdpStartClient(object objectFilename, int CallDuration, out int threadId, out string receivedXmlData)
{
  string filename = (string)objectFilename;
  receivedXmlData = null; Thread.Sleep(CallDuration);
  threadId = Thread.CurrentThread.ManagedThreadId;
  try
  {
    Console.WriteLine("1: UdpStartClient Async - id: " + threadId + " objectFilename: " + (string)objectFilename);
    fileToSend = fileLocation + filename;
    // Send a file to the UdpSocket 
    UdpSendXmlFile(fileToSend, udpClient, bytes, CallDuration, out threadId);

    TimeSpan maxTime = TimeSpan.FromSeconds(10);
    Stopwatch stopwatch = Stopwatch.StartNew();
    bool stopwatchStop = false;

    while (stopwatch.Elapsed < maxTime && !stopwatchStop)
    {
      // listed on UdpSocket and save to file 
      UdpReceivedXmlFileDirectToFile("c:\\Received" + filename, udpClient, remoteEPReceived, CallDuration, out threadId);
      attributXMLReceived = ReadXmlAttribut("c:\\Received" + filename, CallDuration, out threadId);

      if ((attributXMLReceived == "Status=Pending") || (attributXMLReceived == "Status=Sent"))
      {
        Console.WriteLine("Answer from XMl file:" + attributXMLReceived + " id: " + Thread.CurrentThread.ManagedThreadId + "\n");
      }
      else if (attributXMLReceived == "Status=Delivered")
      {
        Console.WriteLine("Answer from XMl file:" + attributXMLReceived + " id: " + Thread.CurrentThread.ManagedThreadId + "\n");
        stopwatchStop = true;
      }
      if (stopwatch.Elapsed == maxTime)
        Console.WriteLine("Timeout!");
    }
  }
  catch (Exception e)
  {
    Console.WriteLine(e.ToString());
  }
}

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1 回答 1

2

这就是 UDP 的工作原理。

UDP 是一种在连接到 IP 网络的设备之间提供不可靠、无序的数据传输的协议。它通常被认为是 OSI 堆栈中的“第 4 层”协议。UDP 的一种流行用途是传输时间敏感信息，例如 IP 语音。UDP 在 RFC 768 中指定。

http://www.techabulary.com/u/udp/

您要么需要使用 TCP，要么准备好处理无序（并且可能完全丢失）响应。

SCTP是传输协议的另一种选择。

于 2013-08-25T19:12:51.243 回答