C#对接PHP上传文件

/// <summary>
        /// 上传文件
        /// </summary>
        /// <param name="fileAdress">文件地址</param>
        /// <returns></returns>
        public responseObject UploadFile(string fileAdress)
        {
            //服务器地址
            string url = "服务器地址";
            //post请求地址
            string postRequestAddress = "post请求地址";
            //请求参数    注意这里请求参数中不包括要上传文件的那个请求参数
            Dictionary<string, string> RequestParameters = new Dictionary<string, string>();
            RequestParameters.Add("请求参数名1", "请求参数值1");
            RequestParameters.Add("请求参数名2", "请求参数值2");
            
            //发送上传文件
            string responseStr =HttpPostFile(url + "/api_pc_cashier/" + postRequestAddress, RequestParameters,fileAdress);
            //将返回的数据解析为对象
            responseObject responseObj = JsonConvert.DeserializeObject<responseObject>(responseStr);
            return responseObj;
        }
        /// <summary>
        /// 上传文件
        /// </summary>
        /// <param name="Url">服务器地址</param>
        /// <param name="postParameter">请求参数</param>
        /// <param name="fileAdress">文件地址 </param>
        /// <param name="isSuccess"></param>
        /// <returns></returns>
        public static string HttpPostFile(string Url, Dictionary<string, string> RequestParameters, string fileAdress)
        {
            // 要上传的文件 
 
            FileStream fs = new FileStream(fileAdress, FileMode.Open, FileAccess.Read);
            BinaryReader r = new BinaryReader(fs);
            //时间戳做分隔符  
            string strBoundary = "----------" + DateTime.Now.Ticks.ToString("x");
            byte[] boundaryBytes = Encoding.ASCII.GetBytes("\r\n--" + strBoundary + "\r\n");     //请求头部信息   
            StringBuilder sb = new StringBuilder();
 
            //构造POST请求体                                                   
            foreach (KeyValuePair<string, string> item in RequestParameters)
            {
                sb.Append("--");
                sb.Append(strBoundary);
                sb.Append("\r\n")
                        .Append("Content-Disposition: form-data; name=\"")
                        .Append(item.Key + "\"").Append("\r\n")
                        .Append("\r\n").Append(item.Value).Append("\r\n");
            }
 
 
 
            sb.Append("--");
            sb.Append(strBoundary);
            sb.Append("\r\n");
            sb.Append("Content-Disposition: form-data; name=\"");
            sb.Append("imgFile");//注意这里是你请求参数中要上传的文件对应的请求参数名称，
            sb.Append("\"; filename=\"");
            sb.Append(fileAdress);
            sb.Append("\";");
            sb.Append("\r\n");
            sb.Append("Content-Type: ");
            sb.Append("application/octet-stream");
            sb.Append("\r\n");
            sb.Append("\r\n");
            string strPostHeader = sb.ToString();
            byte[] postHeaderBytes = Encoding.UTF8.GetBytes(strPostHeader);     // 根据uri创建HttpWebRequest对象   
            HttpWebRequest httpReq = (HttpWebRequest)WebRequest.Create(new Uri(Url));
            httpReq.Method = "POST";     //对发送的数据不使用缓存   
            httpReq.AllowWriteStreamBuffering = false;     //设置获得响应的超时时间（300秒）   
            httpReq.Timeout = 300000;
            httpReq.ContentType = "multipart/form-data; boundary=" + strBoundary;
            long length = fs.Length + postHeaderBytes.Length + boundaryBytes.Length;
            //long fileLength = fs.Length;
            httpReq.ContentLength = length;
            try
            {
 
                //每次上传4k  
                int bufferLength = 4096;
                byte[] buffer = new byte[bufferLength]; //已上传的字节数   
                long offset = 0;         //开始上传时间   
                DateTime startTime = DateTime.Now;
                int size = r.Read(buffer, 0, bufferLength);
                Stream postStream = httpReq.GetRequestStream();         //发送请求头部消息   
                postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
 
                while (size > 0)
                {
                    postStream.Write(buffer, 0, size);
                    offset += size;
 
                    TimeSpan span = DateTime.Now - startTime;
                    double second = span.TotalSeconds;
                    size = r.Read(buffer, 0, bufferLength);
                }
 
                //添加尾部的时间戳   
                postStream.Write(boundaryBytes, 0, boundaryBytes.Length);
                postStream.Close();
                //获取服务器端的响应   
                WebResponse webRespon = httpReq.GetResponse();
                Stream s = webRespon.GetResponseStream();
                //读取服务器端返回的消息  
                StreamReader sr = new StreamReader(s);
                String sReturnString = sr.ReadLine();
                return sReturnString;
 
            }
            catch(WebException ex)
            {
                HttpWebResponse res = (HttpWebResponse)ex.Response;
                return ex.Message;
            }
            finally
            {
                fs.Close();
                r.Close();
            }
 
 
        }