WebRequest的POST既文件和参数

我想上传文件和发送以及一些参数来使用.NET / C＃我的网站。看了一些教程，要么做一些参数或文件，我已经试过了，没有成功，将它们结合起来。下面是我尝试如何做的：

I'm trying to upload a file and a send along a few parameters to my site using .NET / C#. Having read a few tutorials that do either a few parameters or a file, I've tried, unsuccessfully, to combine them. Here is how I try doing it:

WebRequest req = WebRequest.Create(baseURL + "upload");
req.Credentials = new NetworkCredential(username, password);
String boundary = "B0unD-Ary";
req.ContentType = "multipart/form-data; boundary=" + boundary;
req.Method = "POST";
((HttpWebRequest)req).UserAgent = "UploadTester v0.1";

string postData = "--" + boundary + "\nContent-Disposition: form-data\n";
postData += "myId=123&someFk=456";
postData += "\n--" + boundary + "\nContent-Disposition: form-data; name=\"file\" filename=\"upload.pdf\" Content-Type: application/pdf\n\n";
byte[] byteArray = Encoding.UTF8.GetBytes(postData);

byte[] filedata = null;
using (BinaryReader reader = new BinaryReader(File.OpenRead("myfile.pdf")))
    filedata = reader.ReadBytes((int)reader.BaseStream.Length);

req.ContentLength = byteArray.Length + filedata.Length;
req.GetRequestStream().Write(byteArray, 0, byteArray.Length);
req.GetRequestStream().Write(filedata, 0, filedata.Length);

WebResponse response = req.GetResponse();
Stream data = response.GetResponseStream();
StreamReader sReader = new StreamReader(data);
String sResponse = sReader.ReadToEnd();
response.Close();

当我执行它，我得到一个500的异常，说：头一节有超过10240 bnytes（也许它没有正确终止）和Wireshark告诉我，请求发​​送是一种畸形的包，那里的MIME多是格式不正确。

When I execute it, I get a 500 exception, saying "Header section has more than 10240 bnytes (maybe it is not properly terminated)" and Wireshark informs me that the request sent was a malformed package, where the MIME multipart was malformed.

有可能是几个问题在这里，所以请让我知道所有你能发现的问题

There are probably several issues here, so please let me know all the problems you can spot

更新：以MIME从C＃/。NET分开，我已经催生了一个线程在这里：http://stackoverflow.com/questions/1880002/error-in-mime-packet-for-http-post

Update: to separate MIME from C#/.NET, I've spawned a thread here: http://stackoverflow.com/questions/1880002/error-in-mime-packet-for-http-post

更新2 ：那么后端的确与内容长度的问题，他说，阅读可用的字节数比规定的内容长度。但！如果我减少了内容长度在req.Co​​ntentLength因此，我没有一个缓冲区大小发送数据足够大。有什么建议？

Update 2: So the backend indeed has issues with the content-length, saying that the amount of bytes available for reading is smaller than the stated content-length. BUT! If I reduce the content-length in req.ContentLength accordingly, I don't have a buffer size large enough for sending the data. Any suggestions?

更新3 ：事实上，它看起来像头有太大的尺寸相比多少数据包含

Update 3: Actually, it looks like the header has a too large size compared to how much data it contains