C# 实现微信退款及对帐-编程知识

需求

基础准备

关键代码

操作界面

编辑

退款订单类及方法

退款功能实现

对帐

支付商家后台相关要点

实时交易帐单查询

精确交易帐单查询

小结

需求

在招聘报名系统里，考务费支付是其中一个环节，支付方式很多种，比如银联、微信、支付宝等等。本次我们以微信支付进行举例，在考生注册账号、编写简历、报名职位、被初审核通过等一系列基础的条件的具备下，可以进入支付考务费的环节（笔试费用），我们会为其生成一个支付二维码，考生支付后（无论成功与否），都会记录其支付结果状态。

在实际的应用中，对于支付成功的考生，我们会遇到实现退款的需求，只要包括如下场景：

1、根据政策规定，某些符合全部或部分退款条件的考生。

2、其它未知原因，重复支付订单的考生。

3、其它不可抗力，需求进行退款的考生。

基础准备

在实现功能前，做为企业，我们需要申请一个微信服务号，并成为微信支付商家。

1、申请服务号

申请成功后会获得到 AppId 和 AppSecret 用于后续开发，如关联支付商户、网页授权登录等。

具体指引请参照微信公众平台首页：https://mp.weixin.qq.com/cgi-bin/loginpage

2、成为微信支付商家

申请成功后会获得 Mchid 和 paySignKey 用于微信支付、退款等，请在商家后台务必关联申请的公众号。

具体指引请参照微信支付平台首页：https://pay.weixin.qq.com/index.php/core/home/login

上述两个平台申请成功后，请登录微信支付商家平台，进行如下图操作：

在产品中心、AppID帐号管理、关联 AppID（即申请的服务号）

另外一个重要配置是支付目录，我们写的支付程序需要在这里设置，如下图：

关键代码

操作界面

界面上会显示最近一笔的微信订单支付情况，包括订单号、交费时间、交费金额、退款金额。其中退款金额不能大于成功交费金额，否则会返回失败。另外，还可以显示微信交易跟踪日志列表信息，如果订单号、交易价格、openid、返回信息、交易状态等。

示例界面如下：

退款订单类及方法

实现微信退款，需要在支付商家平台申请退款证书，证书文件保存到自定义的目录中，在退款时指定路径。

退款示例代码如下：

                const string RefundOrderUrl = "https://api.mch.weixin.qq.com/secapi/pay/refund";   //退款申请API地址const string RefundQueryUrl = "https://api.mch.weixin.qq.com/pay/refundquery";  //退款查询API地址
//退款订单明细类
public class RefundOrderDetail{/// <summary>/// 返回状态码，SUCCESS/FAIL 此字段是通信标识，非交易标识，交易是否成功需要查看trade_state来判断/// </summary>public string return_code = "";/// <summary>/// 返回信息返回信息，如非空，为错误原因 签名失败 参数格式校验错误/// </summary>public string return_msg = "";/// <summary>/// 业务结果,SUCCESS/FAIL/// </summary>public string result_code = "";/// <summary>/// 错误代码/// </summary>public string err_code = "";/// <summary>/// 错误代码描述/// </summary>public string err_code_des = "";/// <summary>/// 公众号ID(微信分配的公众账号 ID)/// </summary>public string appid = "";/// <summary>/// 商户号(微信支付分配的商户号)/// </summary>public string mch_id = "";/// <summary>/// 微信支付分配的终端设备号/// </summary>public string device_info = "";/// <summary>/// 随机字符串，不长于32位/// </summary>public string nonce_str = "";/// <summary>/// 签名/// </summary>public string sign = "";/// <summary>/// 微信支付订单号/// </summary>public string transaction_id = "";/// <summary>/// 商户系统的订单号，与请求一致。/// </summary>public string out_trade_no = "";public string out_refund_no = "";public string refund_id = "";public string refund_fee = "";public string settlement_refund_fee = "";/// <summary>/// 订单总金额，单位为分/// </summary>public string total_fee = "";/// </summary>public string settlement_total_fee = "";public string fee_type = "";public string cash_fee = "";public string cash_fee_type = "";public string cash_refund_fee = "";public string coupon_type_0 = "";public string coupon_refund_fee = "";public string coupon_refund_fee_0 = "";public string coupon_refund_count = "";public string coupon_refund_id_0 = "";}
//退款订单类public class RefundOrder{/// <summary>/// 公众号ID(微信分配的公众账号 ID)/// </summary>public string appid = "";/// <summary>/// 商户号(微信支付分配的商户号)/// </summary>public string mch_id = "";/// <summary>/// 微信支付分配的终端设备号/// </summary>public string device_info = "";/// <summary>/// 随机字符串，不长于 32 位/// </summary>public string nonce_str = "";/// <summary>/// 签名public string sign = "";public string sign_type = "";/// <summary>/// 商户系统内部的订单号,32个字符内、可包含字母,确保在商户系统唯一,详细说明/// </summary>public string transaction_id = "";public string out_trade_no = "";public string out_refund_no = "";/// <summary>/// 订单总金额，单位为分，不能带小数点/// </summary>public int total_fee = 0;public int refund_fee = 0;public string  refund_fee_type = "";public string op_user_id = "";/// <summary>public string refund_account = "";/// <summary>}
//查询对帐订单类public class QueryOrder{/// <summary>/// 公共号ID(微信分配的公众账号 ID)/// </summary>public string appid = "";/// <summary>/// 商户号(微信支付分配的商户号)/// </summary>public string mch_id = "";/// <summary>/// 微信订单号，优先使用/// </summary>public string transaction_id = "";/// <summary>/// 商户系统内部订单号/// </summary>public string out_trade_no = "";/// <summary>/// 随机字符串，不长于 32 位/// </summary>public string nonce_str = "";/// <summary>/// 签名，参与签名参数：appid，mch_id，transaction_id，out_trade_no，nonce_str，key/// </summary>public string sign = "";}//申请退款方法，返回退款订单明细类
//参数refundorder为退款订单类, key 为支付签名KEY,cert为证书地址,password 为证书密码public RefundOrderDetail getRefundOrderDetail(RefundOrder refundorder, string key,string cert,string password){string post_data = getRefundOrderXml(refundorder, key);string request_data = PostXmlAndCertToUrl(RefundOrderUrl, post_data,cert,password);RefundOrderDetail orderdetail = new RefundOrderDetail();SortedDictionary<string, string> requestXML = GetInfoFromXml(request_data);foreach (KeyValuePair<string, string> k in requestXML){switch (k.Key){case "retuen_code":orderdetail.result_code = k.Value;break;case "return_msg":orderdetail.return_msg = k.Value;break;case "result_code":orderdetail.result_code = k.Value;break;case "err_code":orderdetail.err_code = k.Value;break;case "err_code_des":orderdetail.err_code_des = k.Value;break;case "appid":orderdetail.appid = k.Value;break;case "mch_id":orderdetail.mch_id = k.Value;break;case "device_info":orderdetail.device_info = k.Value;break;case "nonce_str":orderdetail.nonce_str = k.Value;break;case "sign":orderdetail.sign = k.Value;break;case "transaction_id":orderdetail.transaction_id = k.Value;break;case "out_trade_no":orderdetail.out_trade_no = k.Value;break;case "out_refund_no":orderdetail.out_refund_no = k.Value;break;case "refund_id":orderdetail.refund_id = k.Value;break;case "refund_fee":orderdetail.refund_fee = k.Value;break;case "total_fee":orderdetail.total_fee = k.Value;break;case "settlement_refund_fee":orderdetail.settlement_refund_fee = k.Value;break;case "settlement_total_fee":orderdetail.settlement_total_fee = k.Value;break;case "fee_type":orderdetail.fee_type = k.Value;break;case "cash_fee":orderdetail.cash_fee = k.Value;break;case "cash_fee_type ":orderdetail.cash_fee_type = k.Value;break;case "cash_refund_fee":orderdetail.cash_refund_fee = k.Value;break;case "coupon_type_0":orderdetail.coupon_type_0 = k.Value;break;case "coupon_refund_fee":orderdetail.coupon_refund_fee = k.Value;break;case "coupon_refund_fee_0":orderdetail.coupon_refund_fee_0 = k.Value;break;case "coupon_refund_count":orderdetail.coupon_refund_count = k.Value;break;case "coupon_refund_id_0":orderdetail.coupon_refund_id_0 = k.Value;break;default:break;}}return orderdetail;}protected string getRefundOrderXml(RefundOrder refundorder, string key){string return_string = string.Empty;SortedDictionary<string, string> sParams = new SortedDictionary<string, string>();sParams.Add("appid", refundorder.appid);sParams.Add("mch_id", refundorder.mch_id);
//                    sParams.Add("transaction_id", refundorder.transaction_id);sParams.Add("out_trade_no", refundorder.out_trade_no);sParams.Add("nonce_str", refundorder.nonce_str);sParams.Add("out_refund_no", refundorder.out_refund_no);sParams.Add("total_fee", refundorder.total_fee.ToString());sParams.Add("refund_fee", refundorder.refund_fee.ToString());sParams.Add("op_user_id", refundorder.op_user_id);refundorder.sign = getsign(sParams, key);sParams.Add("sign", refundorder.sign);//拼接成XML请求数据StringBuilder sbPay = new StringBuilder();foreach (KeyValuePair<string, string> k in sParams){if (k.Key == "attach" || k.Key == "body" || k.Key == "sign"){sbPay.Append("<" + k.Key + "><![CDATA[" + k.Value + "]]></" + k.Key + ">");}else{sbPay.Append("<" + k.Key + ">" + k.Value + "</" + k.Key + ">");}}return_string = string.Format("<xml>{0}</xml>", sbPay.ToString().TrimEnd(','));return return_string;}public string PostXmlAndCertToUrl(string url, string postData,string cert,string password){string resp = string.Empty;ServicePointManager.ServerCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback(CheckValidationResult);//调用证书System.Security.Cryptography.X509Certificates.X509Certificate2 cer = new System.Security.Cryptography.X509Certificates.X509Certificate2(cert, password, System.Security.Cryptography.X509Certificates.X509KeyStorageFlags.PersistKeySet | System.Security.Cryptography.X509Certificates.X509KeyStorageFlags.MachineKeySet);HttpWebRequest webrequest = (HttpWebRequest)HttpWebRequest.Create(url);webrequest.ClientCertificates.Add(cer);webrequest.Method = "post";webrequest.ContentType = "application/x-www-form-urlencoded";webrequest.ContentLength = postData.Length;//webrequest.ContentType = "text/xml";//byte[] data = System.Text.Encoding.UTF8.GetBytes(postData);//webrequest.ContentLength = data.Length;HttpWebResponse response = null;try{StreamWriter swRequestWriter = new StreamWriter(webrequest.GetRequestStream());swRequestWriter.Write(postData);if (swRequestWriter != null)swRequestWriter.Close();response = (HttpWebResponse)webrequest.GetResponse();using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8)){resp = reader.ReadToEnd();}}catch (Exception exp){throw exp;}finally{if (response != null)response.Close();}return resp;}public string getNoncestr(){Random random = new Random();return GetMD5(random.Next(1000).ToString(), "GBK").ToLower().Replace("s", "S");}

退款功能实现

假设点击退款按钮事件

protected void Button_Click(object sender, EventArgs e)
{string appId = “”； //服务号的appIdstring paySignKey = “”； //申请的支付签名KEY;string mch_id = “”;  //申请的支付商户IDstring OrderID = "";  //支付订单号string OrderAmount = (Convert.ToInt32((float.Parse(Amount.Text) * 100))).ToString();  //订单支付金额，Amount.Text 支付金额string RefundOrderAmount = (Convert.ToInt32((float.Parse(Amount.Text) * 100))).ToString();   //退款金额（Amount.Text）这里表示全额退款string RefundOrderID = Guid.NewGuid().ToString().Replace("-", "");   //生成退款订单号//创建退款订单RefundOrder order = new RefundOrder();order.appid = appId;order.mch_id = mch_id;order.out_trade_no = OrderID;order.nonce_str = tenpay.getNoncestr();order.out_refund_no = RefundOrderID;order.total_fee = int.Parse(OrderAmount);order.refund_fee = int.Parse(RefundOrderAmount);order.op_user_id = mch_id;string cert = “d:\\apiclient_cert.p12";  //退款证书路径//私钥（在安装证书时设置）string password =""; //证书密码
//创建订单明细类，调用getRefundOrderDetail方法进行退款RefundOrderDetail orderdetail = getRefundOrderDetail(order, paySignKey, cert, password);string rv = ("退款订单号:" + RefundOrderID + "<br>");try{rv += ("退款金额:" + (double.Parse(orderdetail.total_fee) / 100).ToString() + "<br>");}catch (Exception eee){rv += ("退款金额:<br>");}rv += ("<b>交易状态:&nbsp;" + (orderdetail.result_code == "SUCCESS" ? "退款申请成功" : "退款申请失败") + "(" + orderdetail.result_code + ")" + "</b><br>");rv += ("可能的错误描述:" + orderdetail.err_code_des);
}

对帐

退款申请成功后，仅为申请状态，需要通过查询退款情况以确定是否完成，该功能可以在考生方进行实现，考生可随时查询自己的对帐情况。

以下是参考代码，该代码可实现支付与退款的查询：

protected void queryOrder(object sender, EventArgs e)
{string OrderID =”“; //订单号string paytype = ”“；  //查询类型，支付消费或退款string appId = "";   //服务号 appidstring paySignKey = "";   //支付签名keystring mch_id = "";    //支付商户号if (paytype == "消费"){try{string openid = ”“;   QueryOrder order = new QueryOrder();order.appid = appId;order.mch_id = mch_id;order.out_trade_no = OrderID;order.nonce_str = getNoncestr();OrderDetail orderdetail = getOrderDetail(order, paySignKey);string rv = ("订单号:" + OrderID + "<br>");rv += ("付款人ID比对识别:" + (openid == orderdetail.openid ? "成功" : "失败") + "<br>");rv += ("交易金额:" + (double.Parse(orderdetail.total_fee) / 100).ToString() + "<br>");rv += ("<b>交易状态:&nbsp;" + (orderdetail.trade_state == "SUCCESS" ? "成功" : "失败") + "(" + orderdetail.trade_state + ")" + "</b><br>");rv += ("支付交易时间:" + (orderdetail.time_end != "" && orderdetail.time_end.Length == 14 ? orderdetail.time_end.Substring(0, 4) + "-" + orderdetail.time_end.Substring(4, 2) + "-" + orderdetail.time_end.Substring(6, 2) + " " + orderdetail.time_end.Substring(8, 2) + ":" + orderdetail.time_end.Substring(10, 2) + ":" + orderdetail.time_end.Substring(12, 2) : "") + "<br>");}catch (Exception ex){return;}}else if (paytype == "退款"){try{RefundOrder order = new RefundOrder();order.appid = appId;order.mch_id = mch_id;order.out_trade_no = OrderID;order.nonce_str = getNoncestr();RefundOrderDetail orderdetail = getRefundQueryOrderDetail(order, paySignKey);string rv = ("<b>交易状态:&nbsp;" + (orderdetail.result_code == "SUCCESS" ? "成功" : "失败") + "(" + orderdetail.result_code + ")" + "</b><br>");rv += ("其它说明:" + orderdetail.err_code_des);}catch (Exception ex){}}
}