.net版，微信免充值代金卷业务开通验收代码

请先下载官方的DEMO，下载地址：https://pay.weixin.qq.com/wiki/doc/api/download/WxPayAPI_CS.zip

然后做如下修改，先修改Config.cs为自己的商户号，密钥，公众号等信息

在Data.cs代码文件增加一个方法用于，生成沙箱测试的签名

        /// <summary>
        /// 获取沙箱密钥
        /// </summary>
        /// <returns></returns>
        public string MakeSandboxSign()
        {
            //转url格式
            string str = ToUrl();
            //在string后加入API KEY
            str += "&key=" + WxPayApi.SandboxGetSignKey().GetValue("sandbox_signkey");
            //MD5加密
            var md5 = MD5.Create();
            var bs = md5.ComputeHash(Encoding.UTF8.GetBytes(str));
            var sb = new StringBuilder();
            foreach (byte b in bs)
            {
                sb.Append(b.ToString("x2"));
            }
            //所有字符转为大写
            return sb.ToString().ToUpper();
        }

在WxPayApi.cs文件中增加下列几个方法，完成业务逻辑，这里采用的是1003+1004+1005示例验收方式，

 /// <summary>
        /// 获取沙箱密钥
        /// </summary>
        /// <returns></returns>
        public static WxPayData SandboxGetSignKey()
        {

            string url = "https://api.mch.weixin.qq.com/sandboxnew/pay/getsignkey"; //沙箱密钥获取api
            WxPayData wpd = new WxPayData();
            wpd.SetValue("mch_id", WxPayConfig.MCHID);
            wpd.SetValue("nonce_str", GenerateNonceStr());
            wpd.SetValue("sign", wpd.MakeSign());
            string xml = wpd.ToXml();
            var start = DateTime.Now; //请求开始时间
            string response = HttpService.Post(xml, url, false, 6);
            var end = DateTime.Now;
            int timeCost = (int) ((end - start).TotalMilliseconds);
            WxPayData result = new WxPayData();
            result.FromXml(response);
            ReportCostTime(url, timeCost, result); //测速上报
            return result;
        }

        /// <summary>
        /// 创建一个订单
        /// </summary>
        /// <param name="OutTradeNo"></param>
        /// <returns></returns>
        public  static  WxPayData SandboxCreateOrder(string OutTradeNo)
        {
            string url = "https://api.mch.weixin.qq.com/sandboxnew/pay/unifiedorder"; 
            WxPayData wpd = new WxPayData();
            wpd.SetValue("appid", WxPayConfig.APPID);
            wpd.SetValue("mch_id", WxPayConfig.MCHID);
            wpd.SetValue("nonce_str", WxPayApi.GenerateNonceStr());
            wpd.SetValue("body", "验收测试");
            wpd.SetValue("out_trade_no", OutTradeNo);
            wpd.SetValue("total_fee", "552");//1003测试此处为551，1004测试完毕要改为552
            wpd.SetValue("spbill_create_ip", "127.0.0.1");
            wpd.SetValue("notify_url", "http://www.weixin.qq.com/wxpay/pay.php");
            wpd.SetValue("trade_type", "NATIVE");
            wpd.SetValue("sign", wpd.MakeSandboxSign());
            string xml = wpd.ToXml();
            var start = DateTime.Now; //请求开始时间
            string response = HttpService.Post(xml, url, false, 6);
            var end = DateTime.Now;
            int timeCost = (int)((end - start).TotalMilliseconds);
            WxPayData result = new WxPayData();
            result.FromXml(response);
            ReportCostTime(url, timeCost, result); //测速上报
            return result;
        }

        /// <summary>
        /// 订单查询
        /// </summary>
        /// <param name="OutTradeNo"></param>
        /// <returns></returns>
        public static WxPayData SandboxQuery(string OutTradeNo)
        {
            string url = "https://api.mch.weixin.qq.com/sandboxnew/pay/orderquery"; 
            WxPayData wpd = new WxPayData();
            wpd.SetValue("appid", WxPayConfig.APPID);
            wpd.SetValue("mch_id", WxPayConfig.MCHID);
            wpd.SetValue("nonce_str", WxPayApi.GenerateNonceStr());
            wpd.SetValue("out_trade_no", OutTradeNo);
            wpd.SetValue("sign", wpd.MakeSandboxSign());
            string xml = wpd.ToXml();
            var start = DateTime.Now; //请求开始时间
            string response = HttpService.Post(xml, url, false, 6);
            var end = DateTime.Now;
            int timeCost = (int)((end - start).TotalMilliseconds);
            WxPayData result = new WxPayData();
            result.FromXml(response);
            ReportCostTime(url, timeCost, result); //测速上报
            return result;
        }

        /// <summary>
        /// 发起退款
        /// </summary>
        /// <param name="OutTradeNo"></param>
        /// <param name="OutRefundNo">退款单号</param>
        /// <returns></returns>
        public static WxPayData SandboxRefund(string OutTradeNo, string OutRefundNo)
        {
            string url = "https://api.mch.weixin.qq.com/sandboxnew/pay/refund";
            WxPayData wpd = new WxPayData();
            wpd.SetValue("appid", WxPayConfig.APPID);
            wpd.SetValue("mch_id", WxPayConfig.MCHID);
            wpd.SetValue("nonce_str", WxPayApi.GenerateNonceStr());
            wpd.SetValue("out_trade_no", OutTradeNo);
            wpd.SetValue("out_refund_no", OutRefundNo);
            wpd.SetValue("total_fee", "552");
            wpd.SetValue("refund_fee", "551");
            wpd.SetValue("sign", wpd.MakeSandboxSign());
            string xml = wpd.ToXml();
            var start = DateTime.Now; //请求开始时间
            string response = HttpService.Post(xml, url, false, 6);
            var end = DateTime.Now;
            int timeCost = (int) ((end - start).TotalMilliseconds);
            WxPayData result = new WxPayData();
            result.FromXml(response);
            ReportCostTime(url, timeCost, result); //测速上报
            return result;
        }

        /// <summary>
        /// 退款查询
        /// </summary>
        /// <param name="OutTradeNo"></param>
        /// <returns></returns>
        public static WxPayData SandboxRefundQuery(string OutTradeNo)
        {
            string url = "https://api.mch.weixin.qq.com/sandboxnew/pay/refundquery";
            WxPayData wpd = new WxPayData();
            wpd.SetValue("appid", WxPayConfig.APPID);
            wpd.SetValue("mch_id", WxPayConfig.MCHID);
            wpd.SetValue("nonce_str", WxPayApi.GenerateNonceStr());
            wpd.SetValue("out_trade_no", OutTradeNo);
            wpd.SetValue("sign", wpd.MakeSandboxSign());
            string xml = wpd.ToXml();
            var start = DateTime.Now; //请求开始时间
            string response = HttpService.Post(xml, url, false, 6);
            var end = DateTime.Now;
            int timeCost = (int)((end - start).TotalMilliseconds);
            WxPayData result = new WxPayData();
            result.FromXml(response);
            ReportCostTime(url, timeCost, result); //测速上报
            return result;
        }

        /// <summary>
        /// /下载对账单
        /// </summary>
        /// <param name="BillDate"></param>
        /// <param name="BillType"></param>
        /// <returns></returns>
        public static WxPayData SandboxDownBill(string BillDate, string BillType)
        {
            string url = "https://api.mch.weixin.qq.com/sandboxnew/pay/downloadbill";
            WxPayData wpd = new WxPayData();
            wpd.SetValue("appid", WxPayConfig.APPID);
            wpd.SetValue("mch_id", WxPayConfig.MCHID);
            wpd.SetValue("nonce_str", WxPayApi.GenerateNonceStr());
            wpd.SetValue("bill_date", BillDate);
            wpd.SetValue("bill_type", BillType);
            wpd.SetValue("sign", wpd.MakeSandboxSign());
            string xml = wpd.ToXml();
            var start = DateTime.Now; //请求开始时间
            string response = HttpService.Post(xml, url, false, 6);
            var end = DateTime.Now;
            int timeCost = (int) ((end - start).TotalMilliseconds);
            WxPayData result = new WxPayData();
            result.FromXml(response);
            ReportCostTime(url, timeCost, result); //测速上报
            return result;
        }

前台测试页面代码

    public partial class test : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                string outTradeNo = DateTime.Now.ToString("yyyyMMddHHMMssfff");
                Label1.Text = outTradeNo;
                WxPayData wpd = WxPayApi.SandboxCreateOrder(outTradeNo);
                string code_url = wpd.GetValue("code_url").ToString();
                Image1.ImageUrl = "MakeQRCode.aspx?data=" + HttpUtility.UrlEncode(code_url);
                Response.Write(wpd.ToXml());
            }
        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            WxPayData wpd = WxPayApi.SandboxQuery(Label1.Text);
            Label2.Text = wpd.ToPrintStr();
        }

        protected void Button2_Click(object sender, EventArgs e)
        {
            WxPayData wpd = WxPayApi.SandboxRefund(Label1.Text, Label1.Text);
            Label2.Text = wpd.ToPrintStr();
        }

        protected void Button3_Click(object sender, EventArgs e)
        {
            WxPayData wpd = WxPayApi.SandboxRefundQuery(Label1.Text);
            Label2.Text = Unicode2String(wpd.ToPrintStr());
        }

        /// <summary>
        /// Unicode转字符串
        /// </summary>
        /// <param name="source">经过Unicode编码的字符串</param>
        /// <returns>正常字符串</returns>
        public static string Unicode2String(string source)
        {
            return new Regex(@"\u([0-9A-F]{4})", RegexOptions.IgnoreCase | RegexOptions.Compiled).Replace(
                         source, x => string.Empty + Convert.ToChar(Convert.ToUInt16(x.Result("$1"), 16)));
        }

        protected void Button4_Click(object sender, EventArgs e)
        {
            WxPayData wpd = WxPayApi.SandboxDownBill("20190507", "ALL");
            Label2.Text = Unicode2String(wpd.ToXml());
        }

        protected void Button5_Click(object sender, EventArgs e)
        {
            WxPayData wpd = WxPayApi.SandboxDownBill("20190507", "SUCCESS");
            Label2.Text = Unicode2String(wpd.ToXml());
        }

        protected void Button6_Click(object sender, EventArgs e)
        {
            WxPayData wpd = WxPayApi.SandboxDownBill("20190507", "REFUND");
            Label2.Text = Unicode2String(wpd.ToXml());
        }
    }

希望对大家有帮助~