C＃：尝试使用httpwebrequest将文件发送到自托管Web服务时出错

Question

First of all, my server is a self-hosted c# webservice. It works well for my other applications, but now I have to implement a method in it that will be used by a mobile computer with Windows CE 5. I will need to receive a file in my server, so I've written this method:

[System.ServiceModel.OperationContract, WebInvoke(UriTemplate = "test/")]
string testSaveFile(Stream arq);


public string testSaveFile(Stream img) {
    Console.WriteLine("stream received");
    Console.WriteLine("stream size: " + img.Length); //throws "Error 400 Bad Request"
}

And in the mobile computer, using .Net CF 3.5 I've written this method to send the file:

public static string UploadFilesToRemoteUrl( string url, string file ) {
    long length = 0;
    string boundary = "----------------------------" +
            DateTime.Now.Ticks.ToString( "x" );
    HttpWebRequest httpWebRequest2 = ( HttpWebRequest ) WebRequest.Create( url );

    httpWebRequest2.AllowWriteStreamBuffering = true;
    httpWebRequest2.ContentType = "multipart/form-data; boundary=" + boundary;
    httpWebRequest2.Method = "POST";
    httpWebRequest2.KeepAlive = true;
    httpWebRequest2.Credentials =
    System.Net.CredentialCache.DefaultCredentials;
    Stream memStream = new System.IO.MemoryStream();
    byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes( "\r\n--" 
        + boundary + "\r\n" );
    memStream.Write( boundarybytes, 0, boundarybytes.Length );
    length += boundarybytes.Length;
    string headerTemplate = "Content-Disposition: form-data; name=\"file\";"
        +" filename=\"file\"\r\n Content-Type: \"application/octet-stream\"\r\n\r\n";
    string header = headerTemplate;
    byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes( header );
    memStream.Write( headerbytes, 0, headerbytes.Length );
    length += headerbytes.Length;
    FileStream fileStream = new FileStream( file, FileMode.Open,
    FileAccess.Read );
    byte[] buffer = new byte[1024];
    int bytesRead = 0;
    while( ( bytesRead = fileStream.Read( buffer, 0, buffer.Length ) ) != 0 ) {
        memStream.Write( buffer, 0, bytesRead );
        length += bytesRead;
    }
    memStream.Write( boundarybytes, 0, boundarybytes.Length );
    length += boundarybytes.Length;
    fileStream.Close();
    httpWebRequest2.ContentLength = memStream.Length;
    Stream requestStream = httpWebRequest2.GetRequestStream();
    memStream.Position = 0;
    byte[] tempBuffer = new byte[memStream.Length];
    memStream.Read( tempBuffer, 0, tempBuffer.Length );
    memStream.Close();
    requestStream.Write( tempBuffer, 0, tempBuffer.Length );
    requestStream.Close();
    WebResponse webResponse2 = httpWebRequest2.GetResponse();
        // ^ Exception here
    Stream stream2 = webResponse2.GetResponseStream();
    StreamReader reader2 = new StreamReader( stream2 );
    string res = reader2.ReadToEnd();
    webResponse2.Close();
    httpWebRequest2 = null;
    webResponse2 = null;

    return res;
}

And using this method I am able to connect to the server. It even displays the first message ("stream received"). But whenever I try to access the stream, the server returns "Error 400 Bad Request", which appears as an exception on the mobile computer. So how can I send a file from the mobile computer to the server? Can I fix this method or should I try another approach?

The answer to this question say to do it asynchronously but I did it and the same error is returned, and this same server is used by Android apps that do it synchronously and it works.

Thanks in advance.

One other thing: is the multipart/form-data the correct approach to send files to this webmethod?

Answer 1

The problem was not in the sending part. The problem was reading the stream lenghth. The answer to this question helped me.