使用HttpWebRequest POST 文件，带参数

public string HttpUploadFile(string url, string file, string paramName, string contentType, NameValueCollection nvc)

{

string result = string.Empty;

string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");

byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);

wr.ContentType = "multipart/form-data; boundary=" + boundary;

wr.Method = "POST";

wr.KeepAlive = true;

wr.Credentials = System.Net.CredentialCache.DefaultCredentials;

Stream rs = wr.GetRequestStream();

string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";

foreach (string key in nvc.Keys)

{

rs.Write(boundarybytes, 0, boundarybytes.Length);

string formitem = string.Format(formdataTemplate, key, nvc[key]);

byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);

rs.Write(formitembytes, 0, formitembytes.Length);

}

rs.Write(boundarybytes, 0, boundarybytes.Length);

string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";

string header = string.Format(headerTemplate, paramName, file, contentType);

byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);

rs.Write(headerbytes, 0, headerbytes.Length);

FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);

byte[] buffer = new byte[4096];

int bytesRead = 0;

while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)

{

rs.Write(buffer, 0, bytesRead);

}

fileStream.Close();

byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");

rs.Write(trailer, 0, trailer.Length);

rs.Close();

WebResponse wresp = null;

try

{

wresp = wr.GetResponse();

Stream stream2 = wresp.GetResponseStream();

StreamReader reader2 = new StreamReader(stream2);

result = reader2.ReadToEnd();

}

catch (Exception ex)

{

if (wresp != null)

{

wresp.Close();

wresp = null;

}

}

finally

{

wr = null;

}

return result;

}

例子：

NameValueCollection nvc = new NameValueCollection();
nvc.Add("id", "TTR");
nvc.Add("btn-submit-photo", "Upload");
HttpUploadFile("http://your.server.com/upload", 
@"C:\test\test.jpg", "file", "image/jpeg", nvc);