.net core 支付宝，微信支付 二

源码： https://github.com/aspros-luo/Qwerty.Payment/tree/develop

今天开始微信支付

微信支付坑比较多，支付流程也不太一样，微信支付需要先生成预支付单，然后再具体调用

具体参考微信sdk

1：微信支付主体，用于存储键值字典，等相关方法

internal class WxPayData
    {
        public WxPayData()
        {

        }

        //采用排序的Dictionary的好处是方便对数据包进行签名，不用再签名之前再做一次排序
        private SortedDictionary<string, object> m_values = new SortedDictionary<string, object>();

        /**
        * 设置某个字段的值
        * @param key 字段名
         * @param value 字段值
        */
        public void SetValue(string key, object value)
        {
            m_values[key] = value;
        }

        /**
        * 根据字段名获取某个字段的值
        * @param key 字段名
         * @return key对应的字段值
        */
        public object GetValue(string key)
        {
            object o = null;
            m_values.TryGetValue(key, out o);
            return o;
        }

        /**
         * 判断某个字段是否已设置
         * @param key 字段名
         * @return 若字段key已被设置，则返回true，否则返回false
         */
        public bool IsSet(string key)
        {
            object o = null;
            m_values.TryGetValue(key, out o);
            if (null != o)
                return true;
            else
                return false;
        }

        /**
        * @将Dictionary转成xml
        * @return 经转换得到的xml串
        * @throws WxPayException
        **/
        public string ToXml()
        {
            //数据为空时不能转化为xml格式
            if (0 == m_values.Count)
            {
                throw new Exception("WxPayData数据为空!");
            }

            string xml = "<xml>";
            foreach (KeyValuePair<string, object> pair in m_values)
            {
                //字段值不能为null，会影响后续流程
                if (pair.Value == null)
                {
                    throw new Exception("WxPayData内部含有值为null的字段!");
                }

                if (pair.Value.GetType() == typeof(int))
                {
                    xml += "<" + pair.Key + ">" + pair.Value + "</" + pair.Key + ">";
                }
                else if (pair.Value.GetType() == typeof(string))
                {
                    xml += "<" + pair.Key + ">" + "<![CDATA[" + pair.Value + "]]></" + pair.Key + ">";
                }
                else//除了string和int类型不能含有其他数据类型
                {

                    throw new Exception("WxPayData字段数据类型错误!");
                }
            }
            xml += "</xml>";
            return xml;
        }

        /**
        * @将xml转为WxPayData对象并返回对象内部的数据
        * @param string 待转换的xml串
        * @return 经转换得到的Dictionary
        * @throws WxPayException
        */
        public SortedDictionary<string, object> FromXml(string xml)
        {
            if (string.IsNullOrEmpty(xml))
            {
                throw new Exception("将空的xml串转换为WxPayData不合法!");
            }

            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.LoadXml(xml);
            XmlNode xmlNode = xmlDoc.FirstChild;//获取到根节点<xml>
            XmlNodeList nodes = xmlNode.ChildNodes;
            foreach (XmlNode xn in nodes)
            {
                XmlElement xe = (XmlElement)xn;
                m_values[xe.Name] = xe.InnerText;//获取xml的键值对到WxPayData内部的数据中
            }

            try
            {
                //2015-06-29 错误是没有签名
                if (m_values["return_code"].ToString() != "SUCCESS")
                {
                    return m_values;
                }
                CheckSign();//验证签名,不通过会抛异常
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }

            return m_values;
        }

        /**
        * @Dictionary格式转化成url参数格式
        * @ return url格式串, 该串不包含sign字段值
        */
        public string ToUrl()
        {
            string buff = "";
            foreach (KeyValuePair<string, object> pair in m_values)
            {
                if (pair.Value == null)
                {
                    throw new Exception("WxPayData内部含有值为null的字段!");
                }

                if (pair.Key != "sign" && pair.Value.ToString() != "")
                {
                    buff += pair.Key + "=" + pair.Value + "&";
                }
            }
            buff = buff.Trim('&');
            return buff;
        }


        /**
        * @Dictionary格式化成Json
         * @return json串数据
        */
        public string ToJson()
        {
            string jsonStr = JsonConvert.SerializeObject(m_values);
            return jsonStr;
        }

        /**
        * @values格式化成能在Web页面上显示的结果（因为web页面上不能直接输出xml格式的字符串）
        */
        public string ToPrintStr()
        {
            string str = "";
            foreach (KeyValuePair<string, object> pair in m_values)
            {
                if (pair.Value == null)
                {

                    throw new Exception("WxPayData内部含有值为null的字段!");
                }

                str += string.Format("{0}={1}<br>", pair.Key, pair.Value.ToString());
            }

            return str;
        }

        /**
        * @生成签名，详见签名生成算法
        * @return 签名, sign字段不参加签名
        */
        public string MakeSign()
        {
            //转url格式
            string str = ToUrl();
            //在string后加入API KEY
            str += "&key=" + WxPayConfig.KEY;
            //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();
        }

        /**
        * 
        * 检测签名是否正确
        * 正确返回true，错误抛异常
        */
        public bool CheckSign()
        {
            //如果没有设置签名，则跳过检测
            if (!IsSet("sign"))
            {

                throw new Exception("WxPayData签名存在但不合法!");
            }
            //如果设置了签名但是签名为空，则抛异常
            else if (GetValue("sign") == null || GetValue("sign").ToString() == "")
            {

                throw new Exception("WxPayData签名存在但不合法!");
            }

            //获取接收到的签名
            string return_sign = GetValue("sign").ToString();

            //在本地计算新的签名
            string cal_sign = MakeSign();

            if (cal_sign == return_sign)
            {
                return true;
            }


            throw new Exception("WxPayData签名验证错误!");
        }

        /**
        * @获取Dictionary
        */
        public SortedDictionary<string, object> GetValues()
        {
            return m_values;
        }
    }

2：微信支付api类，主要用于一些基础方法，生成时间戳，随机字符，快速上报，退款，退款查询等功能，详见代码，

internal class WxPayApi
    {
        /**
        * 提交被扫支付API
        * 收银员使用扫码设备读取微信用户刷卡授权码以后，二维码或条码信息传送至商户收银台，
        * 由商户收银台或者商户后台调用该接口发起支付。
        * @param WxPayData inputObj 提交给被扫支付API的参数
        * @param int timeOut 超时时间
        * @throws WxPayException
        * @return 成功时返回调用结果，其他抛异常
        */
        public static async Task<WxPayData> Micropay(WxPayData inputObj, int timeOut = 10)
        {
            string url = "https://api.mch.weixin.qq.com/pay/micropay";
            //检测必填参数
            if (!inputObj.IsSet("body"))
            {
                throw new Exception("提交被扫支付API接口中，缺少必填参数body！");
            }
            else if (!inputObj.IsSet("out_trade_no"))
            {
                throw new Exception("提交被扫支付API接口中，缺少必填参数out_trade_no！");
            }
            else if (!inputObj.IsSet("total_fee"))
            {
                throw new Exception("提交被扫支付API接口中，缺少必填参数total_fee！");
            }
            else if (!inputObj.IsSet("auth_code"))
            {
                throw new Exception("提交被扫支付API接口中，缺少必填参数auth_code！");
            }

            inputObj.SetValue("spbill_create_ip", WxPayConfig.IP);//终端ip
            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("nonce_str", Guid.NewGuid().ToString().Replace("-", ""));//随机字符串
            inputObj.SetValue("sign", inputObj.MakeSign());//签名
            string xml = inputObj.ToXml();

            var start = DateTime.Now;//请求开始时间

            string response = await HttpService.Post(xml, url, false, timeOut);//调用HTTP通信接口以提交数据到API


            var end = DateTime.Now;
            int timeCost = (int)((end - start).TotalMilliseconds);//获得接口耗时

            //将xml格式的结果转换为对象以返回
            WxPayData result = new WxPayData();
            result.FromXml(response);

            ReportCostTime(url, timeCost, result);//测速上报

            return result;
        }


        /**
        *    
        * 查询订单
        * @param WxPayData inputObj 提交给查询订单API的参数
        * @param int timeOut 超时时间
        * @throws WxPayException
        * @return 成功时返回订单查询结果，其他抛异常
        */
        public static async Task<WxPayData> OrderQuery(WxPayData inputObj, int timeOut = 6)
        {
            string url = "https://api.mch.weixin.qq.com/pay/orderquery";
            //检测必填参数
            if (!inputObj.IsSet("out_trade_no") && !inputObj.IsSet("transaction_id"))
            {
                throw new Exception("订单查询接口中，out_trade_no、transaction_id至少填一个！");
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("nonce_str", GenerateNonceStr());//随机字符串
            inputObj.SetValue("sign", inputObj.MakeSign());//签名

            string xml = inputObj.ToXml();

            var start = DateTime.Now;

            string response = await HttpService.Post(xml, url, false, timeOut);//调用HTTP通信接口提交数据

            var end = DateTime.Now;
            int timeCost = (int)((end - start).TotalMilliseconds);//获得接口耗时

            //将xml格式的数据转化为对象以返回
            WxPayData result = new WxPayData();
            result.FromXml(response);

            ReportCostTime(url, timeCost, result);//测速上报

            return result;
        }


        /**
        * 
        * 撤销订单API接口
        * @param WxPayData inputObj 提交给撤销订单API接口的参数，out_trade_no和transaction_id必填一个
        * @param int timeOut 接口超时时间
        * @throws WxPayException
        * @return 成功时返回API调用结果，其他抛异常
        */
        public static async Task<WxPayData> Reverse(WxPayData inputObj, int timeOut = 6)
        {
            string url = "https://api.mch.weixin.qq.com/secapi/pay/reverse";
            //检测必填参数
            if (!inputObj.IsSet("out_trade_no") && !inputObj.IsSet("transaction_id"))
            {
                throw new Exception("撤销订单API接口中，参数out_trade_no和transaction_id必须填写一个！");
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("nonce_str", GenerateNonceStr());//随机字符串
            inputObj.SetValue("sign", inputObj.MakeSign());//签名
            string xml = inputObj.ToXml();

            var start = DateTime.Now;//请求开始时间


            string response = await HttpService.Post(xml, url, true, timeOut);


            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;
        }


        /**
        * 
        * 申请退款
        * @param WxPayData inputObj 提交给申请退款API的参数
        * @param int timeOut 超时时间
        * @throws WxPayException
        * @return 成功时返回接口调用结果，其他抛异常
        */
        public static async Task<WxPayData> Refund(WxPayData inputObj, int timeOut = 6)
        {
            string url = "https://api.mch.weixin.qq.com/secapi/pay/refund";
            //检测必填参数
            if (!inputObj.IsSet("out_trade_no") && !inputObj.IsSet("transaction_id"))
            {
                throw new Exception("退款申请接口中，out_trade_no、transaction_id至少填一个！");
            }
            else if (!inputObj.IsSet("out_refund_no"))
            {
                throw new Exception("退款申请接口中，缺少必填参数out_refund_no！");
            }
            else if (!inputObj.IsSet("total_fee"))
            {
                throw new Exception("退款申请接口中，缺少必填参数total_fee！");
            }
            else if (!inputObj.IsSet("refund_fee"))
            {
                throw new Exception("退款申请接口中，缺少必填参数refund_fee！");
            }
            else if (!inputObj.IsSet("op_user_id"))
            {
                throw new Exception("退款申请接口中，缺少必填参数op_user_id！");
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("nonce_str", Guid.NewGuid().ToString().Replace("-", ""));//随机字符串
            inputObj.SetValue("sign", inputObj.MakeSign());//签名

            string xml = inputObj.ToXml();
            var start = DateTime.Now;

            string response = await HttpService.Post(xml, url, true, timeOut);//调用HTTP通信接口提交数据到API

            var end = DateTime.Now;
            int timeCost = (int)((end - start).TotalMilliseconds);//获得接口耗时

            //将xml格式的结果转换为对象以返回
            WxPayData result = new WxPayData();
            result.FromXml(response);

            ReportCostTime(url, timeCost, result);//测速上报

            return result;
        }


        /**
        * 
        * 查询退款
        * 提交退款申请后，通过该接口查询退款状态。退款有一定延时，
        * 用零钱支付的退款20分钟内到账，银行卡支付的退款3个工作日后重新查询退款状态。
        * out_refund_no、out_trade_no、transaction_id、refund_id四个参数必填一个
        * @param WxPayData inputObj 提交给查询退款API的参数
        * @param int timeOut 接口超时时间
        * @throws WxPayException
        * @return 成功时返回，其他抛异常
        */
        public static async Task<WxPayData> RefundQuery(WxPayData inputObj, int timeOut = 6)
        {
            string url = "https://api.mch.weixin.qq.com/pay/refundquery";
            //检测必填参数
            if (!inputObj.IsSet("out_refund_no") && !inputObj.IsSet("out_trade_no") &&
                !inputObj.IsSet("transaction_id") && !inputObj.IsSet("refund_id"))
            {
                throw new Exception("退款查询接口中，out_refund_no、out_trade_no、transaction_id、refund_id四个参数必填一个！");
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("nonce_str", GenerateNonceStr());//随机字符串
            inputObj.SetValue("sign", inputObj.MakeSign());//签名

            string xml = inputObj.ToXml();

            var start = DateTime.Now;//请求开始时间

            string response = await HttpService.Post(xml, url, false, timeOut);//调用HTTP通信接口以提交数据到API

            var end = DateTime.Now;
            int timeCost = (int)((end - start).TotalMilliseconds);//获得接口耗时

            //将xml格式的结果转换为对象以返回
            WxPayData result = new WxPayData();
            result.FromXml(response);

            ReportCostTime(url, timeCost, result);//测速上报

            return result;
        }


        /**
        * 下载对账单
        * @param WxPayData inputObj 提交给下载对账单API的参数
        * @param int timeOut 接口超时时间
        * @throws WxPayException
        * @return 成功时返回，其他抛异常
        */
        public static async Task<WxPayData> DownloadBill(WxPayData inputObj, int timeOut = 6)
        {
            string url = "https://api.mch.weixin.qq.com/pay/downloadbill";
            //检测必填参数
            if (!inputObj.IsSet("bill_date"))
            {
                throw new Exception("对账单接口中，缺少必填参数bill_date！");
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("nonce_str", GenerateNonceStr());//随机字符串
            inputObj.SetValue("sign", inputObj.MakeSign());//签名

            string xml = inputObj.ToXml();

            string response = await HttpService.Post(xml, url, false, timeOut);//调用HTTP通信接口以提交数据到API

            WxPayData result = new WxPayData();
            //若接口调用失败会返回xml格式的结果
            if (response.Substring(0, 5) == "<xml>")
            {
                result.FromXml(response);
            }
            //接口调用成功则返回非xml格式的数据
            else
                result.SetValue("result", response);

            return result;
        }


        /**
        * 
        * 转换短链接
        * 该接口主要用于扫码原生支付模式一中的二维码链接转成短链接(weixin://wxpay/s/XXXXXX)，
        * 减小二维码数据量，提升扫描速度和精确度。
        * @param WxPayData inputObj 提交给转换短连接API的参数
        * @param int timeOut 接口超时时间
        * @throws WxPayException
        * @return 成功时返回，其他抛异常
        */
        public static async Task<WxPayData> ShortUrl(WxPayData inputObj, int timeOut = 6)
        {
            string url = "https://api.mch.weixin.qq.com/tools/shorturl";
            //检测必填参数
            if (!inputObj.IsSet("long_url"))
            {
                throw new Exception("需要转换的URL，签名用原串，传输需URL encode！");
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("nonce_str", GenerateNonceStr());//随机字符串    
            inputObj.SetValue("sign", inputObj.MakeSign());//签名
            string xml = inputObj.ToXml();

            var start = DateTime.Now;//请求开始时间

            string response = await HttpService.Post(xml, url, false, timeOut);

            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;
        }


        /**
        * 
        * 统一下单
        * @param WxPaydata inputObj 提交给统一下单API的参数
        * @param int timeOut 超时时间
        * @throws WxPayException
        * @return 成功时返回，其他抛异常
        */
        public static async Task<WxPayData> UnifiedOrder(WxPayData inputObj, int timeOut = 6)
        {
            string url = "https://api.mch.weixin.qq.com/pay/unifiedorder";
            //检测必填参数
            if (!inputObj.IsSet("out_trade_no"))
            {
                throw new Exception("缺少统一支付接口必填参数out_trade_no！");
            }
            else if (!inputObj.IsSet("body"))
            {
                throw new Exception("缺少统一支付接口必填参数body！");
            }
            else if (!inputObj.IsSet("total_fee"))
            {
                throw new Exception("缺少统一支付接口必填参数total_fee！");
            }
            else if (!inputObj.IsSet("trade_type"))
            {
                throw new Exception("缺少统一支付接口必填参数trade_type！");
            }

            //关联参数
            if (inputObj.GetValue("trade_type").ToString() == "JSAPI" && !inputObj.IsSet("openid"))
            {
                throw new Exception("统一支付接口中，缺少必填参数openid！trade_type为JSAPI时，openid为必填参数！");
            }
            if (inputObj.GetValue("trade_type").ToString() == "NATIVE" && !inputObj.IsSet("product_id"))
            {
                throw new Exception("统一支付接口中，缺少必填参数product_id！trade_type为JSAPI时，product_id为必填参数！");
            }

            //异步通知url未设置，则使用配置文件中的url
            if (!inputObj.IsSet("notify_url"))
            {
                inputObj.SetValue("notify_url", WxPayConfig.NOTIFY_URL);//异步通知url
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            //inputObj.SetValue("spbill_create_ip", WxPayConfig.IP);//终端ip              
            inputObj.SetValue("nonce_str", GenerateNonceStr());//随机字符串

            //签名
            inputObj.SetValue("sign", inputObj.MakeSign());
            string xml = inputObj.ToXml();

            var start = DateTime.Now;

            string response = await HttpService.Post(xml, url, false, timeOut);

            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;
        }


        /**
        * 
        * 关闭订单
        * @param WxPayData inputObj 提交给关闭订单API的参数
        * @param int timeOut 接口超时时间
        * @throws WxPayException
        * @return 成功时返回，其他抛异常
        */
        public static async Task<WxPayData> CloseOrder(WxPayData inputObj, int timeOut = 6)
        {
            string url = "https://api.mch.weixin.qq.com/pay/closeorder";
            //检测必填参数
            if (!inputObj.IsSet("out_trade_no"))
            {
                throw new Exception("关闭订单接口中，out_trade_no必填！");
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("nonce_str", GenerateNonceStr());//随机字符串        
            inputObj.SetValue("sign", inputObj.MakeSign());//签名
            string xml = inputObj.ToXml();

            var start = DateTime.Now;//请求开始时间

            string response = await HttpService.Post(xml, url, false, timeOut);

            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;
        }


        /**
        * 
        * 测速上报
        * @param string interface_url 接口URL
        * @param int timeCost 接口耗时
        * @param WxPayData inputObj参数数组
        */
        private static async void ReportCostTime(string interfaceUrl, int timeCost, WxPayData inputObj)
        {
            //如果不需要进行上报

            //如果仅失败上报
            if (inputObj.IsSet("return_code") && inputObj.GetValue("return_code").ToString() == "SUCCESS" &&
             inputObj.IsSet("result_code") && inputObj.GetValue("result_code").ToString() == "SUCCESS")
            {
                return;
            }

            //上报逻辑
            WxPayData data = new WxPayData();
            data.SetValue("interface_url", interfaceUrl);
            data.SetValue("execute_time_", timeCost);
            //返回状态码
            if (inputObj.IsSet("return_code"))
            {
                data.SetValue("return_code", inputObj.GetValue("return_code"));
            }
            //返回信息
            if (inputObj.IsSet("return_msg"))
            {
                data.SetValue("return_msg", inputObj.GetValue("return_msg"));
            }
            //业务结果
            if (inputObj.IsSet("result_code"))
            {
                data.SetValue("result_code", inputObj.GetValue("result_code"));
            }
            //错误代码
            if (inputObj.IsSet("err_code"))
            {
                data.SetValue("err_code", inputObj.GetValue("err_code"));
            }
            //错误代码描述
            if (inputObj.IsSet("err_code_des"))
            {
                data.SetValue("err_code_des", inputObj.GetValue("err_code_des"));
            }
            //商户订单号
            if (inputObj.IsSet("out_trade_no"))
            {
                data.SetValue("out_trade_no", inputObj.GetValue("out_trade_no"));
            }
            //设备号
            if (inputObj.IsSet("device_info"))
            {
                data.SetValue("device_info", inputObj.GetValue("device_info"));
            }

            try
            {
                await Report(data);
            }
            catch (Exception)
            {
                //不做任何处理
            }
        }


        /**
        * 
        * 测速上报接口实现
        * @param WxPayData inputObj 提交给测速上报接口的参数
        * @param int timeOut 测速上报接口超时时间
        * @throws WxPayException
        * @return 成功时返回测速上报接口返回的结果，其他抛异常
        */
        public static async Task<WxPayData> Report(WxPayData inputObj, int timeOut = 1)
        {
            string url = "https://api.mch.weixin.qq.com/payitil/report";
            //检测必填参数
            if (!inputObj.IsSet("interface_url"))
            {
                throw new Exception("接口URL，缺少必填参数interface_url！");
            }
            if (!inputObj.IsSet("return_code"))
            {
                throw new Exception("返回状态码，缺少必填参数return_code！");
            }
            if (!inputObj.IsSet("result_code"))
            {
                throw new Exception("业务结果，缺少必填参数result_code！");
            }
            if (!inputObj.IsSet("user_ip"))
            {
                throw new Exception("访问接口IP，缺少必填参数user_ip！");
            }
            if (!inputObj.IsSet("execute_time_"))
            {
                throw new Exception("接口耗时，缺少必填参数execute_time_！");
            }

            inputObj.SetValue("appid", WxPayConfig.APPID);//公众账号ID
            inputObj.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            inputObj.SetValue("user_ip", WxPayConfig.IP);//终端ip
            inputObj.SetValue("time", DateTime.Now.ToString("yyyyMMddHHmmss"));//商户上报时间     
            inputObj.SetValue("nonce_str", GenerateNonceStr());//随机字符串
            inputObj.SetValue("sign", inputObj.MakeSign());//签名
            string xml = inputObj.ToXml();

            string response = await HttpService.Post(xml, url, false, timeOut);

            WxPayData result = new WxPayData();
            result.FromXml(response);
            return result;
        }

        /**
        * 根据当前系统时间加随机序列来生成订单号
         * @return 订单号
        */
        public static string GenerateOutTradeNo()
        {
            var ran = new Random();
            return string.Format("{0}{1}{2}", WxPayConfig.MCHID, DateTime.Now.ToString("yyyyMMddHHmmss"), ran.Next(999));
        }

        /**
        * 生成时间戳，标准北京时间，时区为东八区，自1970年1月1日 0点0分0秒以来的秒数
         * @return 时间戳
        */
        public static string GenerateTimeStamp()
        {
            TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
            return Convert.ToInt64(ts.TotalSeconds).ToString();
        }

        /**
        * 生成随机串，随机串包含字母或数字
        * @return 随机串
        */
        public static string GenerateNonceStr()
        {
            return Guid.NewGuid().ToString().Replace("-", "");
        }
    }

3：支付业务主体类，这里要优先解决app支付，app支付的坑比较多

    internal class AppPay
    {
        public async Task<WxPayData> Run(string body, string outTradeNo, int totalFee)
        {
            var data = new WxPayData();
            data.SetValue("body", body);//商品描述
            //data.SetValue("attach", outTradeIds);//附加数据
            data.SetValue("out_trade_no", outTradeNo);//随机字符串
            data.SetValue("total_fee", totalFee);//总金额
            data.SetValue("time_start", DateTime.Now.ToString("yyyyMMddHHmmss"));//交易起始时间
            data.SetValue("time_expire", DateTime.Now.AddMinutes(10).ToString("yyyyMMddHHmmss"));//交易结束时间
            //data.SetValue("goods_tag", "jjj");//商品标记
            data.SetValue("trade_type", "APP");//交易类型
            var result = await WxPayApi.UnifiedOrder(data);//调用统一下单接口
            return result;
        }
    }

创建支付主体类，将支付信息填充进去，调用wxapi统一下单方法，返回数据

因为app支付需要二次加签，所以返回的数据需要解析后，再次加签，将返回的数据给app调用sdk支付

二次加签方法：

 public string AppSign(string preJson)
        {
            var dic = JsonConvert.DeserializeObject<Dictionary<string, string>>(preJson);
            var data = new WxPayData();
            data.SetValue("appid", dic["appid"]);
            data.SetValue("partnerid", dic["mch_id"]);
            data.SetValue("prepayid", dic["prepay_id"]);
            data.SetValue("package", "Sign=WXPay");
            data.SetValue("noncestr", WxPayApi.GenerateNonceStr());
            data.SetValue("timestamp", WxPayApi.GenerateTimeStamp());
            data.SetValue("sign", data.MakeSign());
            return data.ToJson();
        }

值得注意的地方是：

a.timestamp用当前时间戳在Android端亦是可行，iOS不行，所以这里依然使用wxpayapi里面的获取时间戳方法

b.partnerid对应的是mchid，即商户号

其他支付业务类

/// <summary>
    /// 微信公众号支付
    /// </summary>
    internal class JsApiPay
    {
        /// <summary>
        /// 保存页面对象，因为要在类的方法中使用Page的Request对象
        /// </summary>
        //private HttpContext page { get; set; }

        /// <summary>
        /// openid用于调用统一下单接口
        /// </summary>
        //public string openid { get; set; }

        /// <summary>
        /// access_token用于获取收货地址js函数入口参数
        /// </summary>
        //public string access_token { get; set; }

        /// <summary>
        /// 商品金额，用于统一下单
        /// </summary>
        //public int total_fee { get; set; }

        /// <summary>
        /// 统一下单接口返回结果
        /// </summary>
        private WxPayData _unifiedOrderResult { get; set; }

        //public JsApiPay(HttpContext page)
        //{
        //    this.page = page;
        //}
        public JsApiPay()
        {

        }

        /**
        * 
        * 网页授权获取用户基本信息的全部过程
        * 详情请参看网页授权获取用户基本信息：http://mp.weixin.qq.com/wiki/17/c0f37d5704f0b64713d5d2c37b468d75.html
        * 第一步：利用url跳转获取code
        * 第二步：利用code去获取openid和access_token
        * 
        */
        //public void GetOpenidAndAccessToken(string tradeId)
        //{
        //    if (!string.IsNullOrEmpty(page.Request.Form["code"]))
        //    {
        //        //获取code码，以获取openid和access_token
        //        string code = page.Request.Form["code"];
        //        //Log.Debug(this.GetType().ToString(), "Get code : " + code);
        //        GetOpenidAndAccessTokenFromCode(code);
        //    }
        //    else
        //    {
        //        //构造网页授权获取code的URL
        //        string redirect_uri = WebUtility.UrlEncode("http://m.aiqinhaigou.com/payment/wechat_callback.html?tradeId=" + tradeId);
        //        WxPayData data = new WxPayData();
        //        data.SetValue("appid", WxPayConfig.APPID);
        //        data.SetValue("redirect_uri", redirect_uri);
        //        data.SetValue("response_type", "code");
        //        data.SetValue("scope", "snsapi_base");
        //        data.SetValue("state", "STATE" + "#wechat_redirect");
        //        string url = "https://open.weixin.qq.com/connect/oauth2/authorize?" + data.ToUrl();
        //        //Log.Debug(this.GetType().ToString(), "Will Redirect to URL : " + url);
        //        try
        //        {
        //            //触发微信返回code码         
        //            page.Response.Redirect(url);//Redirect函数会抛出ThreadAbortException异常，不用处理这个异常
        //        }
        //        catch (Exception ex)
        //        {
        //            throw new Exception(ex.ToString());
        //        }
        //    }
        //}

        /// <summary>
        /// 获取回Openid
        /// </summary>
        /// <returns></returns>
        //public string GetOauthCode(string tradeId)
        //{
        //    //构造网页授权获取code的URL
        //    string redirect_uri = WebUtility.UrlEncode("http://m.aiqinhaigou.com/payment/wechat_callback.html?tradeId=" + tradeId);
        //    WxPayData data = new WxPayData();
        //    data.SetValue("appid", WxPayConfig.APPID);
        //    data.SetValue("redirect_uri", redirect_uri);
        //    data.SetValue("response_type", "code");
        //    data.SetValue("scope", "snsapi_base");
        //    data.SetValue("state", "STATE" + "#wechat_redirect");
        //    var url = "https://open.weixin.qq.com/connect/oauth2/authorize?" + data.ToUrl();
        //    //LogManager.GetLogger(typeof(JsApiPay)).Info("微信支付回调地址：{0}", redirect_uri);
        //    return url;
        //}
        /**
        * 
        * 通过code换取网页授权access_token和openid的返回数据，正确时返回的JSON数据包如下：
        * {
        *  "access_token":"ACCESS_TOKEN",
        *  "expires_in":7200,
        *  "refresh_token":"REFRESH_TOKEN",
        *  "openid":"OPENID",
        *  "scope":"SCOPE",
        *  "unionid": "o6_bmasdasdsad6_2sgVt7hMZOPfL"
        * }
        * 其中access_token可用于获取共享收货地址
        * openid是微信支付jsapi支付接口统一下单时必须的参数
        * 更详细的说明请参考网页授权获取用户基本信息：http://mp.weixin.qq.com/wiki/17/c0f37d5704f0b64713d5d2c37b468d75.html
        * @失败时抛异常WxPayException
        */
        //public void GetOpenidAndAccessTokenFromCode(string code)
        //{
        //    try
        //    {
        //        //构造获取openid及access_token的url
        //        WxPayData data = new WxPayData();
        //        data.SetValue("appid", WxPayConfig.APPID);
        //        data.SetValue("secret", WxPayConfig.APPSECRET);
        //        data.SetValue("code", code);
        //        data.SetValue("grant_type", "authorization_code");
        //        string url = "https://api.weixin.qq.com/sns/oauth2/access_token?" + data.ToUrl();

        //        //请求url以获取数据
        //        string result = HttpService.Get(url);

        //        //Log.Debug(this.GetType().ToString(), "GetOpenidAndAccessTokenFromCode response : " + result);

        //        //保存access_token，用于收货地址获取 
        //        var jd = JObject.Parse(result);
        //        access_token = (string)jd["access_token"];

        //        //获取用户openid
        //        openid = (string)jd["openid"];

        //        //Log.Debug(this.GetType().ToString(), "Get openid : " + openid);
        //        //Log.Debug(this.GetType().ToString(), "Get access_token : " + access_token);
        //    }
        //    catch (Exception ex)
        //    {
        //        //Log.Error(this.GetType().ToString(), ex.ToString());
        //        throw new Exception(ex.ToString());
        //    }
        //}
        /**
         * 调用统一下单，获得下单结果
         * @return 统一下单结果
         * @失败时抛异常WxPayException
         */
        public async Task<WxPayData> GetUnifiedOrderResult(string body, string outTradeNo, int totalFee, string openId)
        {
            //统一下单
            var data = new WxPayData();
            data.SetValue("body", body);
            //data.SetValue("attach", outTradeIds);
            data.SetValue("out_trade_no", outTradeNo);
            data.SetValue("total_fee", totalFee);
            data.SetValue("time_start", DateTime.Now.ToString("yyyyMMddHHmmss"));
            data.SetValue("time_expire", DateTime.Now.AddMinutes(10).ToString("yyyyMMddHHmmss"));
            //data.SetValue("goods_tag", remark);
            data.SetValue("trade_type", "JSAPI");
            data.SetValue("openid", openId);

            var result = await WxPayApi.UnifiedOrder(data);
            if (!result.IsSet("appid") || !result.IsSet("prepay_id") || result.GetValue("prepay_id").ToString() == "")
            {
                throw new Exception("UnifiedOrder response error!");
            }

            _unifiedOrderResult = result;
            return result;
        }

        /**
        *  
        * 从统一下单成功返回的数据中获取微信浏览器调起jsapi支付所需的参数，
        * 微信浏览器调起JSAPI时的输入参数格式如下：
        * {
        *   "appId" : "wx2421b1c4370ec43b",     //公众号名称，由商户传入     
        *   "timeStamp":" 1395712654",         //时间戳，自1970年以来的秒数     
        *   "nonceStr" : "e61463f8efa94090b1f366cccfbbb444", //随机串     
        *   "package" : "prepay_id=u802345jgfjsdfgsdg888",     
        *   "signType" : "MD5",         //微信签名方式:    
        *   "paySign" : "70EA570631E4BB79628FBCA90534C63FF7FADD89" //微信签名 
        * }
        * @return string 微信浏览器调起JSAPI时的输入参数，json格式可以直接做参数用
        * 更详细的说明请参考网页端调起支付API：http://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=7_7
        * 
        */
        public string GetJsApiParameters()
        {
            WxPayData jsApiParam = new WxPayData();
            jsApiParam.SetValue("appId", _unifiedOrderResult.GetValue("appid"));
            jsApiParam.SetValue("timeStamp", WxPayApi.GenerateTimeStamp());
            jsApiParam.SetValue("nonceStr", WxPayApi.GenerateNonceStr());
            jsApiParam.SetValue("package", "prepay_id=" + _unifiedOrderResult.GetValue("prepay_id"));
            jsApiParam.SetValue("signType", "MD5");
            jsApiParam.SetValue("paySign", jsApiParam.MakeSign());

            string parameters = jsApiParam.ToJson();
            return parameters;
        }
    }

/// <summary>
    /// 微信H5支付
    /// </summary>
    internal class MwebPay
    {
        public async Task<WxPayData> GetPayUrl(string body, string outTradeNo, int totalFee, string ip)
        {
            var data = new WxPayData();
            data.SetValue("body", body);//商品描述
            //data.SetValue("attach", outTradeIds);//附加数据
            data.SetValue("out_trade_no", outTradeNo);//随机字符串
            data.SetValue("total_fee", totalFee);//总金额
            data.SetValue("time_start", DateTime.Now.ToString("yyyyMMddHHmmss"));//交易起始时间
            data.SetValue("time_expire", DateTime.Now.AddMinutes(10).ToString("yyyyMMddHHmmss"));//交易结束时间
            //data.SetValue("goods_tag", "jjj");//商品标记
            data.SetValue("trade_type", "MWEB");//交易类型
            data.SetValue("spbill_create_ip", ip);//终端ip     

            var result = await WxPayApi.UnifiedOrder(data);//调用统一下单接口
            return result;
        }

        public string GetJsApiParameters(WxPayData unifiedOrderResult)
        {
            WxPayData jsApiParam = new WxPayData();
            jsApiParam.SetValue("appId", unifiedOrderResult.GetValue("appid"));
            jsApiParam.SetValue("timeStamp", WxPayApi.GenerateTimeStamp());
            jsApiParam.SetValue("nonceStr", WxPayApi.GenerateNonceStr());
            jsApiParam.SetValue("package", "prepay_id=" + unifiedOrderResult.GetValue("prepay_id"));
            jsApiParam.SetValue("signType", "MD5");
            jsApiParam.SetValue("paySign", jsApiParam.MakeSign());

            string parameters = jsApiParam.ToJson();
            return parameters;
        }
    }

  /// <summary>
    /// 微信扫码支付
    /// </summary>
    internal class NativePay
    {
        /**
        * 生成扫描支付模式一URL
        * @param productId 商品ID
        * @return 模式一URL
        */
        public string GetPrePayUrl(string productId)
        {
            //Log.Info(this.GetType().ToString(), "Native pay mode 1 url is producing...");
            WxPayData data = new WxPayData();
            data.SetValue("appid", WxPayConfig.APPID);//公众帐号id
            data.SetValue("mch_id", WxPayConfig.MCHID);//商户号
            data.SetValue("time_stamp", WxPayApi.GenerateTimeStamp());//时间戳
            data.SetValue("nonce_str", WxPayApi.GenerateNonceStr());//随机字符串
            data.SetValue("product_id", productId);//商品ID
            data.SetValue("sign", data.MakeSign());//签名
            var str = ToUrlParams(data.GetValues());//转换为URL串
            var url = "weixin://wxpay/bizpayurl?" + str;
            //Log.Info(this.GetType().ToString(), "Get native pay mode 1 url : " + url);
            return url;
        }

        /**
        * 生成直接支付url，支付url有效期为2小时,模式二
        * @param productId 商品ID
        * @return 模式二URL
        */
        public async Task<string> GetPayUrl(string body, string outTradeNo, int totalFee, string productId)
        {
            //Log.Info(this.GetType().ToString(), "Native pay mode 2 url is producing...");

            var data = new WxPayData();
            data.SetValue("body", body);//商品描述
            //data.SetValue("attach", outTradeIds);//附加数据
            data.SetValue("out_trade_no", outTradeNo);//随机字符串
            data.SetValue("total_fee", totalFee);//总金额
            data.SetValue("time_start", DateTime.Now.ToString("yyyyMMddHHmmss"));//交易起始时间
            data.SetValue("time_expire", DateTime.Now.AddMinutes(10).ToString("yyyyMMddHHmmss"));//交易结束时间
            //data.SetValue("goods_tag", "jjj");//商品标记
            data.SetValue("trade_type", "NATIVE");//交易类型
            data.SetValue("product_id", productId);//商品ID

            var result = await WxPayApi.UnifiedOrder(data);//调用统一下单接口
            string url = result.GetValue("code_url").ToString();//获得统一下单接口返回的二维码链接

            //Log.Info(this.GetType().ToString(), "Get native pay mode 2 url : " + url);
            return url;
        }

        /**
        * 参数数组转换为url格式
        * @param map 参数名与参数值的映射表
        * @return URL字符串
        */
        private string ToUrlParams(SortedDictionary<string, object> map)
        {
            string buff = "";
            foreach (KeyValuePair<string, object> pair in map)
            {
                buff += pair.Key + "=" + pair.Value + "&";
            }
            buff = buff.Trim('&');
            return buff;
        }
    }

4：定义接口

public interface IWxPayService
    {
        /// <summary>
        /// 微信扫码支付，用户发送数据到服务器，返回支付二维码字段
        /// </summary>
        /// <returns></returns>
        Task<Tuple<bool, string>> PagePay(string body, string outTradeNo, int totalFee, string productId);
        /// <summary>
        /// 微信app支付，移动端发送数据，服务器统一下单，返回数据用于app支付
        /// </summary>
        /// <returns></returns>
        Task<Tuple<bool, string>> AppPay(string body, string outTradeNo, int totalFee);
        /// <summary>
        /// 微信公众号支付，服务器返回H5调起参数
        /// </summary>
        /// <returns></returns>
        Task<Tuple<bool, string>> JsApiPay(string body, string outTradeNo, int totalFee, string openId);
        /// <summary>
        /// 微信H5支付
        /// </summary>
        /// <returns></returns>
        Task<Tuple<bool, string>> MwebPay(string body, string outTradeNo, int totalFee, string ip);
        /// <summary>
        /// 微信申请退款
        /// </summary>
        /// <returns></returns>
        Task<WeChatRefundResponse> WeChatRefund(string transactionId, string outTradeNo, int totalFee, int refundFee, string outRefundNo);
        /// <summary>
        /// 微信退款查询，用于确认退款是否成功
        /// </summary>
        /// <returns></returns>
        Task<WeChatRefundQueryResponse> WeChatRefundQuery(string refundId, string outRefundNo, string transactionId, string outTradeNo);
        /// <summary>
        /// 微信回调
        /// </summary>
        /// <returns></returns>
        Task<WeChatNotifyRequest> WeChatNotify(Stream weChatReturnData);
    }

5：实现接口方法

public class WxPayService : IWxPayService
    {
        public async Task<Tuple<bool, string>> PagePay(string body, string outTradeNo, int totalFee, string productId)
        {
            try
            {
                var nativePay = new NativePay();
                //生成扫码支付模式二url
                var url2 = await nativePay.GetPayUrl(body, outTradeNo, totalFee, productId);
                //将url生成二维码图片
                var writerSvg = new BarcodeWriterSvg
                {
                    Format = BarcodeFormat.QR_CODE,
                    Options = new QrCodeEncodingOptions
                    {
                        ErrorCorrection = ErrorCorrectionLevel.H
                    }
                };
                var svgImageData = writerSvg.Write(url2);
                return svgImageData == null
                    ? new Tuple<bool, string>(false, "返回数据为空！")
                    : new Tuple<bool, string>(true, svgImageData.ToString());
            }
            catch (Exception e)
            {
                return new Tuple<bool, string>(false, e.Message);
            }
        }

        public async Task<Tuple<bool, string>> AppPay(string body, string outTradeNo, int totalFee)
        {
            try
            {
                var appId = "XX";
                var mchId = "XX";
                var key = "XX";
                WxPayConfig.Config(appId,mchId,key);
                var appPay = new AppPay();
                var result = await appPay.Run(body, outTradeNo, totalFee);
                return result == null
                    ? new Tuple<bool, string>(false, "返回数据为空！")
                    : new Tuple<bool, string>(true, AppSign(result.ToJson()));
            }
            catch (Exception e)
            {
                return new Tuple<bool, string>(false, e.Message);
            }
        }
        public string AppSign(string preJson)
        {
            var dic = JsonConvert.DeserializeObject<Dictionary<string, string>>(preJson);
            var data = new WxPayData();
            data.SetValue("appid", dic["appid"]);
            data.SetValue("partnerid", dic["mch_id"]);
            data.SetValue("prepayid", dic["prepay_id"]);
            data.SetValue("package", "Sign=WXPay");
            data.SetValue("noncestr", WxPayApi.GenerateNonceStr());
            data.SetValue("timestamp", WxPayApi.GenerateTimeStamp());
            data.SetValue("sign", data.MakeSign());
            return data.ToJson();
        }
        public async Task<Tuple<bool, string>> JsApiPay(string body, string outTradeNo, int totalFee, string openId)
        {
            try
            {
                var jsApiPay = new JsApiPay();
                await jsApiPay.GetUnifiedOrderResult(body, outTradeNo, totalFee, openId);
                var wxJsApiParam = jsApiPay.GetJsApiParameters();//获取H5调起JS API参数    
                return wxJsApiParam == null
                    ? new Tuple<bool, string>(false, "返回数据为空！")
                    : new Tuple<bool, string>(true, wxJsApiParam);
            }
            catch (Exception e)
            {
                return new Tuple<bool, string>(false, e.Message);
            }
        }

        public async Task<Tuple<bool, string>> MwebPay(string body, string outTradeNo, int totalFee, string ip)
        {
            try
            {
                var mwebPay = new MwebPay();
                var data = await mwebPay.GetPayUrl(body, outTradeNo, totalFee, ip);
                return data == null
                    ? new Tuple<bool, string>(false, "返回数据为空！")
                    : new Tuple<bool, string>(true, data.GetValue("mweb_url").ToString());
            }
            catch (Exception e)
            {
                return new Tuple<bool, string>(false, e.Message);
            }
        }

        public async Task<WeChatRefundResponse> WeChatRefund(string transactionId, string outTradeNo, int totalFee, int refundFee, string outRefundNo)
        {
            try
            {
                var result = await WxRefund.Run(transactionId, outTradeNo, totalFee, refundFee, outRefundNo);
                var response = JsonConvert.DeserializeObject<WeChatRefundResponse>(result);
                return response;
            }
            catch (Exception e)
            {
                return new WeChatRefundResponse { result_code = "Fail", return_msg = e.Message };
            }
        }

        public async Task<WeChatRefundQueryResponse> WeChatRefundQuery(string refundId, string outRefundNo, string transactionId, string outTradeNo)
        {
            try
            {
                var result = await WxRefundQuery.Run(refundId, outRefundNo, transactionId, outTradeNo);
                var response = JsonConvert.DeserializeObject<WeChatRefundQueryResponse>(result);
                return response;
            }
            catch (Exception e)
            {
                return new WeChatRefundQueryResponse { result_code = "Fail", return_msg = e.Message };
            }
        }

        public async Task<WeChatNotifyRequest> WeChatNotify(Stream weChatReturnData)
        {
            //接收从微信后台POST过来的数据
            var s = weChatReturnData;
            int count;
            var buffer = new byte[1024];
            var builder = new StringBuilder();
            while ((count = s.Read(buffer, 0, 1024)) > 0)
            {
                builder.Append(Encoding.UTF8.GetString(buffer, 0, count));
            }
            s.Flush();
            s.Dispose();
            var notifyData = new WxPayData();
            try
            {
                notifyData.FromXml(builder.ToString());
            }
            catch (Exception e)
            {
                var res = new WxPayData();
                res.SetValue("return_code", "FAIL");
                res.SetValue("return_msg", e.Message);
                return new WeChatNotifyRequest { IsVerify = false, PayNo = "", TradeIds = "", PayTime = "", Sign = "", Content = res.ToXml() };
            }

            //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
                var 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");
                return new WeChatNotifyRequest { IsVerify = false, PayNo = "", TradeIds = "", PayTime = "", Sign = "", Content = res.ToXml() };
            }

            var transactionId = notifyData.GetValue("transaction_id").ToString();
            var tradeIds = notifyData.GetValue("out_trade_no").ToString();
            var payTime = notifyData.GetValue("time_end").ToString();

            //查询订单，判断订单真实性
            if (!await QueryOrder(transactionId))
            {
                //若订单查询失败，则立即返回结果给微信支付后台
                var res = new WxPayData();
                res.SetValue("return_code", "FAIL");
                res.SetValue("return_msg", "订单查询失败");
                return new WeChatNotifyRequest { IsVerify = false, PayNo = "", TradeIds = "", PayTime = "", Sign = "", Content = res.ToXml() };
            }
            //查询订单成功
            else
            {
                var res = new WxPayData();
                res.SetValue("return_code", "SUCCESS");
                res.SetValue("return_msg", "OK");
                return new WeChatNotifyRequest { IsVerify = true, PayNo = transactionId, TradeIds = tradeIds, PayTime = payTime, Sign = "", Content = res.ToXml() };
            }
        }
        //查询订单
        private static async Task<bool> QueryOrder(string transactionId)
        {
            var req = new WxPayData();
            req.SetValue("transaction_id", transactionId);
            var res = await WxPayApi.OrderQuery(req);
            return res.GetValue("return_code").ToString() == "SUCCESS" && res.GetValue("result_code").ToString() == "SUCCESS";
        }
    }

6：其他一些网络请求类，相关配置类

internal class HttpService
    {
        public static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
        {
            //直接确认，否则打不开    
            return true;
        }

        public static async Task<string> Post(string xml, string url, bool isUseCert, int timeout)
        {
            if (isUseCert)
            {
                //商户私钥证书，用于对请求报文进行签名
                var tempSignCert = new X509Certificate2(WxPayConfig.SSLCERT_PATH, WxPayConfig.SSLCERT_PASSWORD);

                var handler = new HttpClientHandler
                {
                    ClientCertificateOptions = ClientCertificateOption.Manual,
                    SslProtocols = SslProtocols.Tls12
                };
                handler.ClientCertificates.Add(tempSignCert);
                handler.SslProtocols = SslProtocols.Tls12 | SslProtocols.Tls11 | SslProtocols.Tls;
                handler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => true;

                using (var client = new HttpClient(handler))
                {
                    var httpContent = new StringContent(xml, Encoding.UTF8, "application/xml");
                    var response = await client.PostAsync(url, httpContent);
                    return await response.Content.ReadAsStringAsync();
                }
            }
            else
            {
                using (var client = new HttpClient())
                {
                    var httpContent = new StringContent(xml, Encoding.UTF8, "application/xml");
                    var response = await client.PostAsync(url, httpContent);
                    return await response.Content.ReadAsStringAsync();
                }
            }
        }
    }

/**
   *     配置账号信息
   */
    internal class WxPayConfig
    {
        //=======【基本信息设置】=====================================
        /* 微信公众号信息配置
        * APPID：绑定支付的APPID（必须配置）
        * MCHID：商户号（必须配置）
        * KEY：商户支付密钥，参考开户邮件设置（必须配置）
        * APPSECRET：公众帐号secert（仅JSAPI支付的时候需要配置）
        */

        public static void Config(string appId, string mchid, string key)
        {
            APPID = appId;
            MCHID = mchid;
            KEY = key;
            SSLCERT_PASSWORD = mchid;
        }

        public static string APPID { get;private set; } = "XXX";
        public static string MCHID { get; private set; } = "XXX";
        public static string KEY { get; private set; } = "XXX";


        public const string APPSECRET = "XXX";

        //=======【证书路径设置】===================================== 
        /* 证书路径,注意应该填写绝对路径（仅退款、撤销订单时需要）
        */
        public const string SSLCERT_PATH = "path";
        public static string SSLCERT_PASSWORD { get; set; } = "XXX";



        //=======【支付结果通知url】===================================== 
        /* 支付结果通知回调url，用于商户接收支付结果
        */
        public const string NOTIFY_URL = "http://paysdk.weixin.qq.com/example/ResultNotifyPage.aspx";

        //=======【商户系统后台机器IP】===================================== 
        /* 此参数可手动配置也可在程序中自动获取
        */
        public const string IP = "8.8.8.8";


        //=======【代理服务器设置】===================================
        /* 默认IP和端口号分别为0.0.0.0和0，此时不开启代理（如有需要才设置）
        */
        public const string PROXY_URL = "http://10.152.18.220:8080";

        //=======【上报信息配置】===================================
        /* 测速上报等级，0.关闭上报; 1.仅错误时上报; 2.全量上报
        */
        public const int REPORT_LEVENL = 1;

        //=======【日志级别】===================================
        /* 日志等级，0.不输出日志；1.只输出错误信息; 2.输出错误和正常信息; 3.输出错误信息、正常信息和调试信息
        */
        public const int LOG_LEVENL = 0;
    }

值得注意的地方

a.微信退款及撤销支付是需要证书的，.net core 调用证书请求可以参考：http://www.cnblogs.com/AsprosL/p/7234141.html，也可以查看具体代码

b.微信配置类需要设置灵活配置，app支付需要开发平台申请，其他支付方式需要微信公众号开通，所以会有多个appid及mchid

----------------------------分割线------------------------------

以上基本就是微信支付的内容了，支付回调，退款及退款查询预留到下一章节吧