ASP.NET MVC 开发微信支付H5的实现示例（外置浏览器支付）

      Com.Wxpay.WxPayConfig wxConfig = new Com.Wxpay.WxPayConfig();
          Senparc.Weixin.MP.TenPayLibV3.RequestHandler packageReqHandler = new Senparc.Weixin.MP.TenPayLibV3.RequestHandler(null);
          packageReqHandler.SetParameter("appid", wxConfig.appid);//APPID
          packageReqHandler.SetParameter("mch_id", wxConfig.mchid);//商户号
          packageReqHandler.SetParameter("nonce_str", Senparc.Weixin.MP.TenPayLibV3.TenPayV3Util.GetNoncestr());
          packageReqHandler.SetParameter("body", "测试商品");
          packageReqHandler.SetParameter("out_trade_no", model.OrderID);//订单号
          packageReqHandler.SetParameter("total_fee", cost.ToString()); //金额,以分为单位
          packageReqHandler.SetParameter("spbill_create_ip", Request.UserHostAddress);//IP
          packageReqHandler.SetParameter("notify_url", "http://" + HttpContext.Request.Url.Host + "/WxPay/PayNotifyUrl"); //回调地址
          packageReqHandler.SetParameter("trade_type", "MWEB");//这个不可以改。固定为Mweb
          packageReqHandler.SetParameter("sign", packageReqHandler.CreateMd5Sign("key", wxConfig.key));
          string data = packageReqHandler.ParseXML();
          var urlFormat = "https://api.mch.weixin.qq.com/pay/unifiedorder";
          var formDataBytes = data == null ? new byte[0] : Encoding.UTF8.GetBytes(data);
          MemoryStream ms = new MemoryStream();
          ms.Write(formDataBytes, 0, formDataBytes.Length);
          ms.Seek(0, SeekOrigin.Begin);
          var result = RequestUtility.HttpPost(urlFormat, null, ms);

          var res = System.Xml.Linq.XDocument.Parse(result);
          string mweb_url = res.Element("xml").Element("mweb_url").Value;

<xml>
 <return_code><![CDATA[SUCCESS]]></return_code>
 <return_msg><![CDATA[OK]]></return_msg>
 <appid><![CDATA[wx***********]]></appid>
 <mch_id><![CDATA[1*******]]></mch_id>
 <nonce_str><![CDATA[4rN3Sy63EsAErTq7]]></nonce_str>
 <sign><![CDATA[0E34B9B750778540436A5CDF005212CF]]></sign>
 <result_code><![CDATA[SUCCESS]]></result_code>
 <prepay_id><![CDATA[wx201********************************]]></prepay_id>
 <trade_type><![CDATA[MWEB]]></trade_type>
 <mweb_url><![CDATA[https://wx.tenpay.com/cgi-bin/mmpayweb-bin/checkmweb?prepay_id=*******71655&package=1******9]]></mweb_url>
</xml>

    /// <summary>
    /// 支付结果回调地址
    /// </summary>
    /// <returns></returns>
    [HttpPost]
    public virtual ActionResult PayNotifyUrl()
    {
     
      Com.Wxpay.WxPayConfig wxConfig = new Com.Wxpay.WxPayConfig();
      Senparc.Weixin.MP.TenPayLibV3.ResponseHandler payNotifyRepHandler = new Senparc.Weixin.MP.TenPayLibV3.ResponseHandler(null);
      payNotifyRepHandler.SetKey(wxConfig.key);

      string return_code = payNotifyRepHandler.GetParameter("return_code");
      string return_msg = payNotifyRepHandler.GetParameter("return_msg");
      string xml = string.Format(@"<xml><return_code><![CDATA[{0}]]></return_code><return_msg><![CDATA[{1}]]></return_msg></xml>", return_code, return_msg);

      if (return_code.ToUpper() != "SUCCESS")
      {
        return Content(xml, "text/xml");
      }

      string out_trade_no = payNotifyRepHandler.GetParameter("out_trade_no");
      //微信服务器可能会多次推送到本接口，这里需要根据out_trade_no去查询订单是否处理，如果处理直接返回：return Content(xml, "text/xml"); 不跑下面代码

      //验证请求是否从微信发过来（安全）
      if (payNotifyRepHandler.IsTenpaySign())
      {
        //TO DO
      }
      else
      {

      }
      return Content(xml, "text/xml");
    }