C＃：我的回调函数被调用两次，每发送一个请求

我有一个程序，上传/下载文件到一个在线服务器，有一个回调报告进度并将其记录到文本文件中，该程序是用结构如下：C＃：我的回调函数被调用两次，每发送一个请求

public void Upload(string source, string destination) 
{  
     //Object containing Source and destination to pass to the threaded function 
     KeyValuePair<string, string> file = new KeyValuePair<string, string>(source, destination); 
     //Threading to make sure no blocking happens after calling upload Function 
     Thread t = new Thread(new ParameterizedThreadStart(amazonHandler.TUpload)); 
     t.Start(file); 
} 

    private void TUpload(object fileInfo) 
{ 
    KeyValuePair<string, string> file = (KeyValuePair<string, string>)fileInfo; 
    /* 
    Some Magic goes here,Checking The file and Authorizing Upload 
    */ 
    var ftiObject = new FtiObject() 
     { FileNameOnHDD = file.Key, 
      DestinationPath = file.Value, 
      //Has more data used for calculations. 
     }; 
      //Threading to make sure progress gets callback gets called. 
     Thread t = new Thread(new ParameterizedThreadStart(amazonHandler.UploadOP)); 
      t.Start(ftiObject); 
      //Signal used to stop progress untill uploadCompleted is called. 
      uploadChunkDoneSignal.WaitOne(); 
     /* 
      Some Extra Code 
     */ 
} 

private void UploadOP(object ftiSentObject) 
{ 
    FtiObject ftiObject = (FtiObject)ftiSentObject; 
    /* 
    Some useless code to create the uri and prepare the ftiObject. 
    */ 

    // webClient.UploadFileAsync will open a thread that 
    // will upload the file and report 
    // progress/complete using registered callback functions. 

    webClient.UploadFileAsync(uri, "PUT", ftiObject.FileNameOnHDD, ftiObject); 
}

我得到了注册到Web客户端的UploadProgressChanged事件的回调，但它获取调用每次发送的请求两次。

void UploadProgressCallback(object sender, UploadProgressChangedEventArgs e) 
    { 
     FtiObject ftiObject = (FtiObject)e.UserState; 
       Logger.log(ftiObject.FileNameOnHDD, (double)e.BytesSent ,e.TotalBytesToSend); 
    }

日志输出：

Filename: C:\Text1.txt Uploaded:1024 TotalFileSize: 665241 
    Filename: C:\Text1.txt Uploaded:1024 TotalFileSize: 665241 
    Filename: C:\Text1.txt Uploaded:2048 TotalFileSize: 665241 
    Filename: C:\Text1.txt Uploaded:2048 TotalFileSize: 665241 
    Filename: C:\Text1.txt Uploaded:3072 TotalFileSize: 665241 
    Filename: C:\Text1.txt Uploaded:3072 TotalFileSize: 665241 
    Etc...

我使用的是观察者看网络流量，并且只有1请求被发送。

一些我怎么弄清楚为什么回调被调用两次，我的疑问是，回调是由每个线程打开（主要上载和TUpload）被解雇，但我不知道如何测试，如果这就是原因。

注意：许多/ ** /注释背后的原因是表明函数不仅仅是打开线程，而且正在使用线程来确保不会发生阻塞（有一些“Signal.WaitOne（）“围绕代码进行同步）

来源

2010-05-06 Madi D.

如果您在回调中放置了一个断点，难道您不能检查callstack以查看来电的来源吗？如果你使用的是Visual Studio。

来源

2010-05-06 09:26:36

尝试了Callstack它没有帮助..回调被mscorlib.dll调用..如果我尝试断点它..它停止第二点..然而+1帮助我阅读和学习一个新的诀窍：） – 2010-05-06 09:41:06

您是否检查过API是否确实使用UploadProgressChangedEventArgs中的不同信息回调twise？

来源

2010-05-06 09:27:27

看来，webclient本身正在做双重调用，不知何故，它滑倒我的头脑检查“UploadProgressChangedEventArgs”的所有属性，我只检查发送和他们是相同的，但是当我检查接收到的参数，他们改变从-1到0 ..显然是2个不同的调用，与我的线程无关。 – 2010-05-06 09:42:33

C＃：我的回调函数被调用两次，每发送一个请求

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