我有我正在编写的 WPF 应用程序，它可以将文件发布到社交网络之一。 上传本身工作正常，但我想提供一些关于我上传进度的指示。

我尝试了很多方法来做到这一点:

1) HttpWebRequest.GetStream 方法:

using (
 var FS = File.Open(
  localFilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
    long len = FS.Length;
    HttpWebRequest request = (HttpWebRequest) WebRequest.Create(url);
    request.Method = "POST";
    request.ProtocolVersion = HttpVersion.Version11;
    request.ContentType = "multipart/form-data; boundary=--AaB03x";
    //predata and postdata is two byte[] arrays, that contains
    //strings for MIME file upload (defined above and is not important)
    request.ContentLength = predata.Length + FS.Length + postdata.Length;
    request.AllowWriteStreamBuffering = false;
    using (var reqStream = request.GetRequestStream())
    {
        reqStream.Write(predata, 0, predata.Length);
        int bytesRead = 0;
        int totalRead = 0;
        do
        {
            bytesRead = FS.Read(fileData, 0, MaxContentSize);
            totalRead += bytesRead;
            reqStream.Write(fileData, 0, bytesRead);
            reqStream.Flush(); //trying with and without this
            //this part will show progress in percents
            sop.prct = (int) ((100*totalRead)/len);
        } while (bytesRead > 0);
        reqStream.Write(postdata, 0, postdata.Length);
    }
    HttpWebResponse responce = (HttpWebResponse) request.GetResponse();
    using (var respStream = responce.GetResponseStream())
    {
        //do things
    }
}

2) WebClient 方式(更短):

void UploadFile (url, localFilePath)
{
    ...
    WebClient client = new WebClient();
    client.UploadProgressChanged += new UploadProgressChangedEventHandler(UploadPartDone);
    client.UploadFileCompleted += new UploadFileCompletedEventHandler(UploadComplete);
    client.UploadFileAsync(new Uri(url), localFilePath);
    done.WaitOne();

    //do things with responce, received from UploadComplete
    JavaScriptSerializer jssSer = new JavaScriptSerializer();
    return jssSer.Deserialize<UniversalJSONAnswer>(utf8.GetString(UploadFileResponce));
    //so on...
    ...
}

void UploadComplete(object sender, UploadFileCompletedEventArgs e)
{
    UploadFileResponce=e.Result;
    done.Set();
}

void UploadPartDone(object sender, UploadProgressChangedEventArgs e)
{
    //this part expected to show progress
    sop.prct=(int)(100*e.BytesSent/e.TotalBytesToSend);
}

3)连TcpClient方式:

using (
 var FS = File.Open(
  localFilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
    long len = FS.Length;
    long totalRead = 0;
    using (var client = new TcpClient(urli.Host, urli.Port))
    {
        using (var clearstream = client.GetStream())
        {
            using (var writer = new StreamWriter(clearstream))
            using (var reader = new StreamReader(clearstream))
            {
                //set progress to 0
                sop.prct = 0;
                // Send request headers
                writer.WriteLine("POST " + urli.AbsoluteUri + " HTTP/1.1");
                writer.WriteLine("Content-Type: multipart/form-data; boundary=--AaB03x");
                writer.WriteLine("Host: " + urli.Host);
                writer.WriteLine("Content-Length: " + (predata.Length + len + postdata.Length).ToString());
                writer.WriteLine();
                //some data for MIME
                writer.Write(utf8.GetString(predata));
                writer.Flush();
                int bytesRead;
                do
                {
                    bytesRead = FS.Read(fileData, 0, MaxContentSize);
                    totalRead += bytesRead;
                    writer.BaseStream.Write(fileData, 0, bytesRead);
                    writer.BaseStream.Flush();
                    sop.prct = (int) ((100*totalRead)/len);
                } while (bytesRead > 0)
                writer.Write(utf8.GetString(postdata));
                writer.Flush();
                //read line of response and do other thigs...
                respStr = reader.ReadLine();
                ...
            }
        }
    }
}

在所有情况下，文件都已成功发送到服务器。 但进度总是这样:它从 0 运行几秒钟到 100，然后等待文件实际上传(大约 5 分钟 - 文件为 400MB)。

所以我认为来自文件的数据在某处被缓冲，我跟踪的不是上传，而是缓冲数据。然后必须等到它上传。

我的问题是:

1) 有什么方法可以跟踪实际 上传数据吗？ Stream.Write() 或 Flush() 方法(正如我在某处读到的那样，不适用于 NetworkStream)在收到来自服务器的确认已收到 TCP 数据包之前不会返回。

2) 还是我可以拒绝缓冲(HttpWebRequest 的 AllowWriteStreamBUffering 不起作用)？

3) 进一步“向下”尝试使用套接字是否有意义？

更新:

为了避免在 UI 上显示进度的方式出现任何疑问，我重写了代码以记录文件。 所以，这是代码:

using (var LogStream=File.Open("C:\\123.txt",FileMode.Create,FileAccess.Write,FileShare.Read))
using (var LogWriter=new StreamWriter(LogStream))
using (var FS = File.Open(localFilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
    long len = FS.Length;
    HttpWebRequest request = (HttpWebRequest) WebRequest.Create(url);
    request.Timeout = 7200000; //2 hour timeout
    request.Method = "POST";
    request.ProtocolVersion = HttpVersion.Version11;
    request.ContentType = "multipart/form-data; boundary=--AaB03x";
    //predata and postdata is two byte[] arrays, that contains
    //strings for MIME file upload (defined above and is not important)
    request.ContentLength = predata.Length + FS.Length + postdata.Length;
    request.AllowWriteStreamBuffering = false;
    LogWriter.WriteLine(DateTime.Now.ToString("o") + " Start write into request stream. ");
    using (var reqStream = request.GetRequestStream())
    {
        reqStream.Write(predata, 0, predata.Length);
        int bytesRead = 0;
        int totalRead = 0;
        do
        {
            bytesRead = FS.Read(fileData, 0, MaxContentSize);
            totalRead += bytesRead;
            reqStream.Write(fileData, 0, bytesRead);
            reqStream.Flush(); //trying with and without this
            //sop.prct = (int) ((100*totalRead)/len); //this part will show progress in percents
            LogWriter.WriteLine(DateTime.Now.ToString("o") + " totalRead= " + totalRead.ToString() + " / " + len.ToString());
        } while (bytesRead > 0);
        reqStream.Write(postdata, 0, postdata.Length);
    }
    LogWriter.WriteLine(DateTime.Now.ToString("o") + " All sent!!! Waiting for responce... ");
    LogWriter.Flush();
    HttpWebResponse responce = (HttpWebResponse) request.GetResponse();
    LogWriter.WriteLine(DateTime.Now.ToString("o") + " Responce received! ");
    using (var respStream = responce.GetResponseStream())
    {
        if (respStream == null) return null;
        using (var streamReader = new StreamReader(respStream))
        {
            string resp = streamReader.ReadToEnd();
            JavaScriptSerializer jssSer = new JavaScriptSerializer();
            return jssSer.Deserialize<UniversalJSONAnswer>(resp);
        }
    }
}

这是结果(我切掉了中间部分):

2011-11-19T22:00:54.5964408+04:00 Start write into request stream. 
2011-11-19T22:00:54.6404433+04:00 totalRead= 1048576 / 410746880
2011-11-19T22:00:54.6424434+04:00 totalRead= 2097152 / 410746880
2011-11-19T22:00:54.6434435+04:00 totalRead= 3145728 / 410746880
2011-11-19T22:00:54.6454436+04:00 totalRead= 4194304 / 410746880
2011-11-19T22:00:54.6464437+04:00 totalRead= 5242880 / 410746880
2011-11-19T22:00:54.6494438+04:00 totalRead= 6291456 / 410746880
.......    
2011-11-19T22:00:55.3434835+04:00 totalRead= 408944640 / 410746880
2011-11-19T22:00:55.3434835+04:00 totalRead= 409993216 / 410746880
2011-11-19T22:00:55.3464837+04:00 totalRead= 410746880 / 410746880
2011-11-19T22:00:55.3464837+04:00 totalRead= 410746880 / 410746880
2011-11-19T22:00:55.3464837+04:00 All sent!!! Waiting for responce... 
2011-11-19T22:07:23.0616597+04:00 Responce received! 

如您所见，程序认为它上传了大约 400MB，持续了大约 2 秒。 7 分钟后文件实际上传，我收到回复。

再次更新:

似乎这是在 WIndows 7 下发生的(不确定 x64 或 x86)。 当我在 XP 上运行我的代码时，一切正常，进度显示绝对正确

最佳答案

这个问题发布已经一年多了，但我认为我的帖子对某些人有用。

我在显示进度方面遇到了同样的问题，它的表现与您描述的完全一样。所以我决定使用正确显示上传进度的 HttpClient。然后我遇到了有趣的错误——当我启动 Fiddler 时，HttpClient 开始以意想不到的方式显示其上传进度，就像上面的 WebClient/HttpWebRequest 一样，所以我认为这可能是 WebClient 显示上传进度不正确的原因(我想我有它启动了)。所以我再次尝试使用 WebClient(没有启动类似 fiddler 的应用程序)并且一切正常，上传进度具有正确的值。我已经在几台装有 win7 和 XP 的 PC 上进行了测试，在所有情况下都可以正确显示进度。

所以，我认为像 Fiddler 这样的程序(可能不仅仅是一个 fiddler)对 WebClient 和其他 .net 类如何显示上传进度有一些影响。

这个讨论批准了它:

HttpWebRequest doesn't work except when fiddler is running

关于c# - 上传HTTP进度跟踪，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8181114/