public FileResult MakeQRCode(string data)
 {
 if (string.IsNullOrEmpty(data)) 
 throw new ArgumentException("data");
 //初始化二维码生成工具
 QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
 qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
 qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;
 qrCodeEncoder.QRCodeVersion = 0;
 qrCodeEncoder.QRCodeScale = 4;
 //将字符串生成二维码图片
 Bitmap image = qrCodeEncoder.Encode(data, Encoding.Default);
 //保存为PNG到内存流 
 MemoryStream ms = new MemoryStream();
 image.Save(ms, ImageFormat.Jpeg);
 return File(ms.ToArray(), "image/jpeg");
 }

public ActionResult ResultNotify()
 {
 //接收从微信后台POST过来的数据
 Stream s = Request.InputStream;
 int count = 0;
 byte[] buffer = new byte[1024];
 StringBuilder builder = new StringBuilder();
 while ((count = s.Read(buffer, 0, 1024)) > 0)
 {
 builder.Append(Encoding.UTF8.GetString(buffer, 0, count));
 }
 s.Flush();
 s.Close();
 s.Dispose();
 Logger.Info(this.GetType()+ "Receive data from WeChat : " + builder);
 //转换数据格式并验证签名
 WxPayData data = new WxPayData();
 try
 {
 data.FromXml(builder.ToString());
 }
 catch (WxPayException ex)
 {
 //若签名错误，则立即返回结果给微信支付后台
 WxPayData res = new WxPayData();
 res.SetValue("return_code", "FAIL");
 res.SetValue("return_msg", ex.Message);
 Log.Error(this.GetType().ToString(), "Sign check error : " + res.ToXml());
 Response.Write(res.ToXml());
 Response.End();
 }
 Logger.Info(this.GetType()+ "Check sign success");
 ProcessNotify(data);
 return View();
 }
 public void ProcessNotify(WxPayData data)
 {
 WxPayData notifyData = data;
 //检查支付结果中transaction_id是否存在
 if (!notifyData.IsSet("transaction_id"))
 {
 //若transaction_id不存在，则立即返回结果给微信支付后台
 WxPayData res = new WxPayData();
 res.SetValue("return_code", "FAIL");
 res.SetValue("return_msg", "支付结果中微信订单号不存在");
 Logger.Error(this.GetType()+"The Pay result is error : " + res.ToXml());
 Response.Write(res.ToXml());
 Response.End();
 }
 string transaction_id = notifyData.GetValue("transaction_id").ToString();
 //查询订单，判断订单真实性
 if (!QueryOrder(transaction_id))
 {
 //若订单查询失败，则立即返回结果给微信支付后台
 WxPayData res = new WxPayData();
 res.SetValue("return_code", "FAIL");
 res.SetValue("return_msg", "订单查询失败");
 Logger.Error(this.GetType()+"Order query failure : " + res.ToXml());
 Response.Write(res.ToXml());
 Response.End();
 }
 //查询订单成功
 else
 {
 WxPayData res = new WxPayData();
 res.SetValue("return_code", "SUCCESS");
 res.SetValue("return_msg", "OK");
 Logger.Info(this.GetType()+"order query success : " + res.ToXml());
 SetPaymentResult(data.GetValue("out_trade_no").ToString(), PaymentStatus.Paid);
 Response.Write(res.ToXml());
 Response.End();
 }
 }

public void SetPaymentResult(string tradeno, PaymentStatus status)
 {
 Logger.Info("订单号:"+tradeno);
 var order = _orderService.GetOrderByTradeNumber(tradeno);
 if (order != null)
 {
 order.PaymentStatus = status;
 if (status == PaymentStatus.Paid)
 {
 order.PaidDate = DateTime.Now;
 }
 _orderService.UpdateOrder(order);
 Logger.Info("订单："+tradeno+"成功更新状态为"+status);
 }
 }