商戶Native支付下單介面，微信後臺系統返回連結引數code_url，
商戶後臺系統將code_url值生成二維碼圖片，使用者使用微信客戶端掃碼後發起支付。
1.SDK與DEMO下載
https://pay.weixin.qq.com/wiki/doc/api/native.php?chapter=11_1
2.拷貝business與lib資料夾
3.將下載的證書解壓後拷貝到cert資料夾下
4.修改lib資料夾下的DemoConfig檔案

        public string GetAppID(){
            return "繫結支付的APPID";
        }
        public string GetMchID(){
            return "商戶號";
        }
        public string GetKey(){
            return "配置金鑰時輸入的字串";
        }

        public string GetSSlCertPath(){
            return "cert\\apiclient_cert.p12";
        }
        public string GetSSlCertPassword(){
            return "證書密碼";
        }
        public string GetNotifyUrl(){
            return "支付回撥方法";//最好是使用域名
        }
 

5.呼叫API返回支付Url

     NativePay nativePay = new NativePay();
     //生成掃碼支付模式二url
     WxPayModel wxPayModel = new WxPayModel();
     wxPayModel.body = data.body;
     wxPayModel.attach = data.attach;
     wxPayModel.total_fee = data.total_fee;
     wxPayModel.goods_tag = data.goods_tag;
     wxPayModel.trade_type = "NATIVE";
     wxPayModel.product_id = data.product_id;
     wxPayModel.out_trade_no = out_trade_no;

     string url = nativePay.GetPayUrl(wxPayModel);
 

6.根據url生成二維碼

引用 qrcode.js，使用new QRCode生成二維碼圖片
new QRCode(document.getElementById("qrcode"), data.url);

7.支付結果回撥

    var buffer = new byte[Convert.ToInt32(Request.ContentLength)];
    Request.Body.ReadAsync(buffer, 0, buffer.Length);
    var body = Encoding.UTF8.GetString(buffer);//接收到的支付通知

    //將xml格式的結果轉換為物件以返回
    WxPayData results = new WxPayData();
    results.FromXml(body);

    #region  更新訂單狀態
    OrderNotify orderNotify = new OrderNotify();
    orderNotify.return_code = results.GetValue("return_code").ToString();
    if (orderNotify.return_code == "SUCCESS")
    {
         orderNotify.attach = results.GetValue("attach").ToString();
         orderNotify.out_trade_no = results.GetValue("out_trade_no").ToString();
         orderNotify.total_fee = Convert.ToDouble(results.GetValue("total_fee").ToString()) * 0.01;
         orderNotify.transaction_id = results.GetValue("transaction_id").ToString();//微信訂單號
    } 
    else
    {
         msg = "[return_code]返回狀態不為[SUCCESS]";
    }
   #endregion
 

8.支付結果查詢

     WxPayApi wxPayApi = new WxPayApi();
     string transaction_id = data.transaction_id;//微信訂單號
     string out_trade_no = data.out_trade_no;//商戶系統訂單號
     resultmsg = OrderQuery.Run(transaction_id, out_trade_no);//呼叫訂單查詢業務邏輯