自定义交易组件上传图片接口

protected void Button1_Click(object sender, EventArgs e)
        {
            //https://api.weixin.qq.com/shop/img/upload?access_token= //上传图片
           //string accesstoken = AccessTokenContainer.GetAccessToken(ConfigurationManager.AppSettings["WeChat:Appid"].ToString());
            string accesstoken ="获取到的accesstoken";
            Label1.Text = accesstoken;
            string url = "https://api.weixin.qq.com/shop/img/upload?access_token= " + accesstoken;
            Dictionary postDictionary = new Dictionary();
            postDictionary.Add("resp_type", "1");
            postDictionary.Add("upload_type", "0");
            var filepath = HttpContext.Current.Server.MapPath("/images/"+ TextBox1.Text);
            TextArea1.Text = GongYongClass.PostFile(url, postDictionary, filepath, "media");
            TextArea2.Text = filepath;
        }

public static string PostFile(string getUrl, Dictionary postDictionary, string filePath, string fileFormDataName)
        {
        
            string fileName = Path.GetFileName(filePath);
            //Stream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls;//https形式需要添加
            string sReturnString = string.Empty;
            //fileStream.Position = 0;
            string Enter = "\r\n";
            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();

            //添加参数信息
            foreach (var item in postDictionary)
            {
               sb.Append("--"+ strBoundary + Enter + "Content-Disposition: form-data; name=\"" + item.Key + "\""+ Enter+ "Content-Type: text/plain" + Enter + Enter+ item.Value+ Enter);
            }
            //添加文件信息
            sb.Append("--"+ strBoundary + Enter+ "Content-Disposition: form-data; name=\"" + fileFormDataName + "\"; filename=\"" + fileName + "\""+ Enter+ "Content-Type:application/octet-stream" + Enter + Enter);
            byte[] sbbyte = Encoding.UTF8.GetBytes(sb.ToString());//将参数信息+文件头信息转换 二进制编码
            byte[] buffer = File.ReadAllBytes(filePath);  //文件二进制编码
            //合并信息到一起
            byte[] postHeaderBytes= new byte[sbbyte.Length + buffer.Length];
            sbbyte.CopyTo(postHeaderBytes, 0);
            buffer.CopyTo(postHeaderBytes, sbbyte.Length); 
            try
            {
                // 根据uri创建HttpWebRequest对象
                HttpWebRequest httpReq = (HttpWebRequest)WebRequest.Create(new Uri(getUrl));
                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.ServicePoint.Expect100Continue = false;
                //httpReq.CookieContainer = cookieContainer;
                //httpReq.Accept = header["accept"].ToString();
                //httpReq.Headers.Add("Accept-Encoding","gzip, deflate, br");
                //httpReq.Headers.Add("TE", "Trailers");
                // httpReq.UserAgent = header["userAgent"];
                httpReq.ContentType = "multipart/form-data; boundary=" + strBoundary;
             
                long length =  postHeaderBytes.Length + boundaryBytes.Length;
                httpReq.ContentLength = length;
                Stream postStream = httpReq.GetRequestStream();
                //发送请求消息
                postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
                //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
                HttpWebResponse webRespon = (HttpWebResponse)httpReq.GetResponse();
                if (webRespon.StatusCode == HttpStatusCode.OK) //如果服务器未响应，那么继续等待相应                 
                {
                    Stream s = webRespon.GetResponseStream();
                    StreamReader sr = new StreamReader(s);
                    //读取服务器端返回的消息
                    sReturnString = sr.ReadLine();
                    s.Close();
                    sr.Close();
                }
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
            return sReturnString;
        }

未完待补充