模拟form表单请求上传文件

发请求

public string CameraFileUpload(string url,string path,string serverPath,string uploadfileName)
        {

            System.Net.ServicePointManager.DefaultConnectionLimit = 200;
            System.GC.Collect();


            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            CookieContainer cookieContainer = new CookieContainer();
            request.CookieContainer = cookieContainer;
            request.AllowAutoRedirect = true;
            request.KeepAlive = false;
            request.Method = "POST";
            string boundary = DateTime.Now.Ticks.ToString("X"); // 随机分隔线
            request.ContentType = "multipart/form-data;charset=utf-8;boundary=" + boundary;
            byte[] itemBoundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "\r\n");
            byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");

            int pos = path.LastIndexOf("\\");
            string fileName = path.Substring(pos + 1);

            //请求头部信息 
            StringBuilder sbHeader = new StringBuilder(string.Format("Content-Disposition:form-data;name=\"file\";filename=\"{0}\"\r\nContent-Type:application/octet-stream\r\n\r\n", fileName));
            byte[] postHeaderBytes = Encoding.UTF8.GetBytes(sbHeader.ToString());

            request.Headers.Add("serverPath", serverPath);
            request.Headers.Add("uploadfileName", uploadfileName);

            FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read);
            byte[] bArr = new byte[fs.Length];
            fs.Read(bArr, 0, bArr.Length);
            fs.Close();

            Stream postStream = request.GetRequestStream();
            postStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);
            postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
            postStream.Write(bArr, 0, bArr.Length);
            postStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);
            postStream.Close();

            //发送请求并获取相应回应数据
            HttpWebResponse response = request.GetResponse() as HttpWebResponse;
            //直到request.GetResponse()程序才开始向目标网页发送Post请求
            Stream instream = response.GetResponseStream();
            StreamReader sr = new StreamReader(instream, Encoding.UTF8);
            //返回结果网页（html）代码
            string content = sr.ReadToEnd();

            if (request != null)
            {
                request.Abort();
                request = null;
            }
            if (response != null)
            {
                response.Close();
                response = null;
            }

            return content;
        }

处理请求：

 protected void Page_Load(object sender, EventArgs e)
       {
            try
            {
                HttpPostedFile file = Request.Files[0];

                string temp = Request.Form["temp"];
                string serverPath = Request.Headers["serverPath"];
                string uploadfileName = Request.Headers["uploadfileName"];

                filePathCheck(serverPath);
                file.SaveAs(Server.MapPath(serverPath + "\\" + uploadfileName));
                Response.Write("上传成功");
            }
            catch (Exception ex)
            {
                Response.Write("上传失败 原因:" + ex.Message);
            }
        }

        public void filePathCheck(string path)
        {
            if (!Directory.Exists(Server.MapPath(path)))
                Directory.CreateDirectory(Server.MapPath(path));
        }