关于微信小程序获取小程序码并接受buffer流保存为图片的方法

 public static string Api_Post(string postUrl, string postData, WebHeaderCollection header = null,bool isPic=false)
　　　　　{
 Stream outstream = null;
 Stream instream = null;
 StreamReader sr = null;
 HttpWebResponse response = null;
 HttpWebRequest request = null;
 Encoding encoding = Encoding.UTF8;
 byte[] data = encoding.GetBytes(postData);
 // 准备请求...
 try
 {
 // 设置参数
 request = WebRequest.Create(postUrl) as HttpWebRequest;
 CookieContainer cookieContainer = new CookieContainer();
 request.CookieContainer = cookieContainer;
 request.AllowAutoRedirect = true;
 request.Method = "POST";
 request.ContentType = "application/x-www-form-urlencoded";
 if (header != null) request.Headers = header;
 request.ContentLength = data.Length;
 outstream = request.GetRequestStream();
 outstream.Write(data, 0, data.Length);
 outstream.Close();
 //发送请求并获取相应回应数据
 response = request.GetResponse() as HttpWebResponse;
 //直到request.GetResponse()程序才开始向目标网页发送Post请求
 instream = response.GetResponseStream();

 if (isPic)
 {
 byte[] tt = StreamToBytes(instream);//将数据流转为byte[]
 System.IO.File.WriteAllBytes(HttpContext.Current.Server.MapPath("~/WxCode.jpg"), tt);
 WxQRCodeModel model = new WxQRCodeModel();
 model.data = "192.168.1.216:80/WxCode.jpg";
 model.errcode = 0;
 string content = Config.js.Serialize(model);
 string err = string.Empty;
 return content;
 }
 else
 {
 sr = new StreamReader(instream, encoding);
 //返回结果网页（html）代码
 string content = sr.ReadToEnd();
 string err = string.Empty;
 return content;
 }

 }
 catch (Exception ex)
 {
 if (isPic)
 {
 sr = new StreamReader(instream, encoding);
 //返回结果网页（html）代码
 string content = sr.ReadToEnd();
 string err = string.Empty;
 return content;
 }
 else
 {
 string err = ex.Message;
 return string.Empty;
 }
 }
 }

 ///将数据流转为byte[]
 public static byte[] StreamToBytes(Stream stream)
 {
 List<byte> bytes = new List<byte>();
 int temp = stream.ReadByte();
 while (temp != -1)
 {
 bytes.Add((byte)temp);
 temp = stream.ReadByte();
 }
 return bytes.ToArray();
 }