微信公衆號發起微信支付 c#

tenpay.dll：

MD5Util.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;

namespace tenpay
{
    public class MD5Util
    {
        public MD5Util()
        {
            //
            // TODO: 在此處添加構造函數邏輯
            //
        }

        /** 獲取大寫的MD5簽名結果 */
        public static string GetMD5(string encypStr, string charset)
        {
            string retStr;
            MD5CryptoServiceProvider m5 = new MD5CryptoServiceProvider();

            //建立md5對象
            byte[] inputBye;
            byte[] outputBye;

            //使用GB2312編碼方式把字符串轉化爲字節數組．
            try
            {
                inputBye = Encoding.GetEncoding(charset).GetBytes(encypStr);
            }
            catch (Exception ex)
            {
                inputBye = Encoding.GetEncoding("GB2312").GetBytes(encypStr);
            }
            outputBye = m5.ComputeHash(inputBye);

            retStr = System.BitConverter.ToString(outputBye);
            retStr = retStr.Replace("-", "").ToUpper();
            return retStr;
        }
    }
}

OrderDetail.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace tenpay
{
    /// <summary>
    /// 微信訂單明細實體對象
    /// </summary>
    [Serializable]
    public class OrderDetail
    {
        /// <summary>
        /// 返回狀態碼，SUCCESS/FAIL 此字段是通訊標識，非交易標識，交易是否成功須要查看trade_state來判斷
        /// </summary>
        public string return_code = "";

        /// <summary>
        /// 返回信息返回信息，如非空，爲錯誤緣由 簽名失敗 參數格式校驗錯誤
        /// </summary>
        public string return_msg = "";

        /// <summary>
        /// 公共號ID(微信分配的公衆帳號 ID)
        /// </summary>
        public string appid = "";

        /// <summary>
        /// 商戶號(微信支付分配的商戶號)
        /// </summary>
        public string mch_id = "";

        /// <summary>
        /// 隨機字符串，不長於32位
        /// </summary>
        public string nonce_str = "";

        /// <summary>
        /// 簽名
        /// </summary>
        public string sign = "";

        /// <summary>
        /// 業務結果,SUCCESS/FAIL
        /// </summary>
        public string result_code = "";

        /// <summary>
        /// 錯誤代碼
        /// </summary>
        public string err_code = "";

        /// <summary>
        /// 錯誤代碼描述
        /// </summary>
        public string err_code_des = "";

        /// <summary>
        /// 交易狀態
        ///SUCCESS—支付成功
        ///REFUND—轉入退款
        ///NOTPAY—未支付
        ///CLOSED—已關閉
        ///REVOKED—已撤銷
        ///USERPAYING--用戶支付中
        ///NOPAY--未支付(輸入密碼或確認支付超時) PAYERROR--支付失敗(其餘緣由，如銀行返回失敗)
        /// </summary>
        public string trade_state = "";

        /// <summary>
        /// 微信支付分配的終端設備號
        /// </summary>
        public string device_info = "";

        /// <summary>
        /// 用戶在商戶appid下的惟一標識
        /// </summary>
        public string openid = "";
       
        /// <summary>
        /// 用戶是否關注公衆帳號，Y-關注，N-未關注，僅在公衆帳號類型支付有效
        /// </summary>
        public string is_subscribe = "";

        /// <summary>
        /// 交易類型,JSAPI、NATIVE、MICROPAY、APP
        /// </summary>
        public string trade_type = "";

        /// <summary>
        /// 銀行類型，採用字符串類型的銀行標識
        /// </summary>
        public string bank_type = "";

        /// <summary>
        /// 訂單總金額，單位爲分
        /// </summary>
        public string total_fee = "";

        /// <summary>
        /// 現金券支付金額<=訂單總金額，訂單總金額-現金券金額爲現金支付金額
        /// </summary>
        public string coupon_fee = "";

        /// <summary>
        /// 貨幣類型，符合ISO 4217標準的三位字母代碼，默認人民幣：CNY
        /// </summary>
        public string fee_type = "";

        /// <summary>
        /// 微信支付訂單號
        /// </summary>
        public string transaction_id = "";

        /// <summary>
        /// 商戶系統的訂單號，與請求一致。
        /// </summary>
        public string out_trade_no = "";

        /// <summary>
        /// 商家數據包，原樣返回
        /// </summary>
        public string attach = "";

        /// <summary>
        /// 支付完成時間，格式爲yyyyMMddhhmmss，如2009年12月27日9點10分10秒錶示爲20091227091010。
        /// 時區爲GMT+8 beijing。該時間取自微信支付服務器
        /// </summary>
        public string time_end = "";

    }
}

QueryOrder.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace tenpay
{
    /// <summary>
    /// 微信訂單查詢接口請求實體對象
    /// </summary>
    [Serializable]
    public class QueryOrder
    {
        /// <summary>
        /// 公共號ID(微信分配的公衆帳號 ID)
        /// </summary>
        public string appid = "";

        /// <summary>
        /// 商戶號(微信支付分配的商戶號)
        /// </summary>
        public string mch_id = "";

        /// <summary>
        /// 微信訂單號，優先使用
        /// </summary>
        public string transaction_id = "";

        /// <summary>
        /// 商戶系統內部訂單號
        /// </summary>
        public string out_trade_no = "";

        /// <summary>
        /// 隨機字符串，不長於 32 位
        /// </summary>
        public string nonce_str = "";

        /// <summary>
        /// 簽名，參與簽名參數：appid，mch_id，transaction_id，out_trade_no，nonce_str，key
        /// </summary>
        public string sign = "";
    }
}

UnifiedOrder.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace tenpay
{
    /// <summary>
    /// 微信統一接口請求實體對象
    /// </summary>
    [Serializable]
    public class UnifiedOrder
    {
        /// <summary>
        /// 公共號ID(微信分配的公衆帳號 ID)
        /// </summary>
        public string appid = "";
        /// <summary>
        /// 商戶號(微信支付分配的商戶號)
        /// </summary>
        public string mch_id = "";
        /// <summary>
        /// 微信支付分配的終端設備號
        /// </summary>
        public string device_info = "";
        /// <summary>
        /// 隨機字符串，不長於 32 位
        /// </summary>
        public string nonce_str = "";
        /// <summary>
        /// 簽名
        /// </summary>
        public string sign = "";
        /// <summary>
        /// 商品描述
        /// </summary>
        public string body = "";
        /// <summary>
        /// 附加數據，原樣返回
        /// </summary>
        public string attach = "";
        /// <summary>
        /// 商戶系統內部的訂單號,32個字符內、可包含字母,確保在商戶系統惟一,詳細說明
        /// </summary>
        public string out_trade_no = "";
        /// <summary>
        /// 訂單總金額，單位爲分，不能帶小數點
        /// </summary>
        public int total_fee = 0;
        /// <summary>
        /// 終端IP
        /// </summary>
        public string spbill_create_ip = "";
        /// <summary>
        /// 訂 單 生 成 時 間 ， 格 式 爲yyyyMMddHHmmss，如 2009 年12 月 25 日 9 點 10 分 10 秒錶示爲 20091225091010。時區爲 GMT+8 beijing。該時間取自商戶服務器
        /// </summary>
        public string time_start = "";
        /// <summary>
        /// 交易結束時間
        /// </summary>
        public string time_expire = "";
        /// <summary>
        /// 商品標記 商品標記，該字段不能隨便填，不使用請填空，使用說明詳見第 5 節
        /// </summary>
        public string goods_tag = "";
        /// <summary>
        /// 接收微信支付成功通知
        /// </summary>
        public string notify_url = "";
        /// <summary>
        /// JSAPI、NATIVE、APP
        /// </summary>
        public string trade_type = "";
        /// <summary>
        /// 用戶標識 trade_type 爲 JSAPI時，此參數必傳
        /// </summary>
        public string openid = "";
        /// <summary>
        /// 只在 trade_type 爲 NATIVE時須要填寫。
        /// </summary>
        public string product_id = "";
    }
}

TenpayUtil.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;

namespace tenpay
{
    public class TenpayUtil
    {
        /// <summary>
        /// 統一支付接口
        /// </summary>
        const string UnifiedPayUrl = "https://api.mch.weixin.qq.com/pay/unifiedorder";

        /// <summary>
        /// 網頁受權接口
        /// </summary>
        const string access_tokenUrl = "https://api.weixin.qq.com/sns/oauth2/access_token";

        /// <summary>
        /// 微信訂單查詢接口
        /// </summary>
        const string OrderQueryUrl = "https://api.mch.weixin.qq.com/pay/orderquery";

        /// <summary>
        /// 隨機串
        /// </summary>
        public static string getNoncestr()
        {
            Random random = new Random();
            return MD5Util.GetMD5(random.Next(1000).ToString(), "GBK").ToLower().Replace("s", "S");
        }

        /// <summary>
        /// 時間截，自1970年以來的秒數
        /// </summary>
        public static string getTimestamp()
        {
            TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
            return Convert.ToInt64(ts.TotalSeconds).ToString();
        }

        /// <summary>
        /// 網頁受權接口
        /// </summary>
        public static string getAccess_tokenUrl()
        {
            return access_tokenUrl;
        }

        /// <summary>
        /// 獲取微信簽名
        /// </summary>
        /// <param name="sParams"></param>
        /// <returns></returns>
        public string getsign(SortedDictionary<string, string> sParams, string key)
        {
            int i = 0;
            string sign = string.Empty;
            StringBuilder sb = new StringBuilder();
            foreach (KeyValuePair<string, string> temp in sParams)
            {
                if (temp.Value == "" || temp.Value == null || temp.Key.ToLower() == "sign")
                {
                    continue;
                }
                i++;
                sb.Append(temp.Key.Trim() + "=" + temp.Value.Trim() + "&");
            }
            sb.Append("key=" + key.Trim() + "");
            string signkey = sb.ToString();
            sign = MD5Util.GetMD5(signkey, "utf-8");


            return sign;
        }

        /// <summary>
        /// post數據到指定接口並返回數據
        /// </summary>
        public string PostXmlToUrl(string url, string postData)
        {
            string returnmsg = "";
            using (System.Net.WebClient wc = new System.Net.WebClient())
            {
                returnmsg = wc.UploadString(url, "POST", postData);
            }
            return returnmsg;
        }

        /// <summary>
        /// 獲取prepay_id
        /// </summary>
        public string getPrepay_id(UnifiedOrder order, string key)
        {
            string prepay_id = "";
            string post_data = getUnifiedOrderXml(order, key);
            string request_data = PostXmlToUrl(UnifiedPayUrl, post_data);
            SortedDictionary<string, string> requestXML = GetInfoFromXml(request_data);
            foreach (KeyValuePair<string, string> k in requestXML)
            {
                if (k.Key == "prepay_id")
                {
                    prepay_id = k.Value;
                    break;
                }
            }
            return prepay_id;
        }

        /// <summary>
        /// 獲取微信訂單明細
        /// </summary>
        public OrderDetail getOrderDetail(QueryOrder queryorder, string key)
        {
            string post_data = getQueryOrderXml(queryorder, key);
            string request_data = PostXmlToUrl(OrderQueryUrl, post_data);
            OrderDetail orderdetail = new OrderDetail();
            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 "appid":
                        orderdetail.appid = k.Value;
                        break;
                    case "mch_id":
                        orderdetail.mch_id = k.Value;
                        break;
                    case "nonce_str":
                        orderdetail.nonce_str = k.Value;
                        break;
                    case "sign":
                        orderdetail.sign = 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 "trade_state":
                        orderdetail.trade_state = k.Value;
                        break;
                    case "device_info":
                        orderdetail.device_info = k.Value;
                        break;
                    case "openid":
                        orderdetail.openid = k.Value;
                        break;
                    case "is_subscribe":
                        orderdetail.is_subscribe = k.Value;
                        break;
                    case "trade_type":
                        orderdetail.trade_type = k.Value;
                        break;
                    case "bank_type":
                        orderdetail.bank_type = k.Value;
                        break;
                    case "total_fee":
                        orderdetail.total_fee = k.Value;
                        break;
                    case "coupon_fee":
                        orderdetail.coupon_fee = k.Value;
                        break;
                    case "fee_type":
                        orderdetail.fee_type = k.Value;
                        break;
                    case "transaction_id":
                        orderdetail.transaction_id = k.Value;
                        break;
                    case "out_trade_no":
                        orderdetail.out_trade_no = k.Value;
                        break;
                    case "attach":
                        orderdetail.attach = k.Value;
                        break;
                    case "time_end":
                        orderdetail.time_end = k.Value;
                        break;
                    default:
                        break;
                }
            }
            return orderdetail;
        }

        /// <summary>
        /// 把XML數據轉換爲SortedDictionary<string, string>集合
        /// </summary>
        /// <param name="strxml"></param>
        /// <returns></returns>
        protected SortedDictionary<string, string> GetInfoFromXml(string xmlstring)
        {
            SortedDictionary<string, string> sParams = new SortedDictionary<string, string>();
            try
            {
                XmlDocument doc = new XmlDocument();
                doc.LoadXml(xmlstring);
                XmlElement root = doc.DocumentElement;
                int len = root.ChildNodes.Count;
                for (int i = 0; i < len; i++)
                {
                    string name = root.ChildNodes[i].Name;
                    if (!sParams.ContainsKey(name))
                    {
                        sParams.Add(name.Trim(), root.ChildNodes[i].InnerText.Trim());
                    }
                }
            }
            catch { }
            return sParams;
        }

        /// <summary>
        /// 微信統一下單接口xml參數整理
        /// </summary>
        /// <param name="order">微信支付參數實例</param>
        /// <param name="key">密鑰</param>
        /// <returns></returns>
        protected string getUnifiedOrderXml(UnifiedOrder order, string key)
        {
            string return_string = string.Empty;
            SortedDictionary<string, string> sParams = new SortedDictionary<string, string>();
            sParams.Add("appid", order.appid);
            sParams.Add("attach", order.attach);
            sParams.Add("body", order.body);
            sParams.Add("device_info", order.device_info);
            sParams.Add("mch_id", order.mch_id);
            sParams.Add("nonce_str", order.nonce_str);
            sParams.Add("notify_url", order.notify_url);
            sParams.Add("openid", order.openid);
            sParams.Add("out_trade_no", order.out_trade_no);
            sParams.Add("spbill_create_ip", order.spbill_create_ip);
            sParams.Add("total_fee", order.total_fee.ToString());
            sParams.Add("trade_type", order.trade_type);
            order.sign = getsign(sParams, key);
            sParams.Add("sign", order.sign);

            //拼接成XML請求數據
            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());
            byte[] byteArray = Encoding.UTF8.GetBytes(return_string);
            return_string = Encoding.GetEncoding("GBK").GetString(byteArray);
            return return_string;
            
        }

        /// <summary>
        /// 微信訂單查詢接口XML參數整理
        /// </summary>
        /// <param name="queryorder">微信訂單查詢參數實例</param>
        /// <param name="key">密鑰</param>
        /// <returns></returns>
        protected string getQueryOrderXml(QueryOrder queryorder, string key)
        {
            string return_string = string.Empty;
            SortedDictionary<string, string> sParams = new SortedDictionary<string, string>();
            sParams.Add("appid", queryorder.appid);
            sParams.Add("mch_id", queryorder.mch_id);
            sParams.Add("transaction_id", queryorder.transaction_id);
            sParams.Add("out_trade_no", queryorder.out_trade_no);
            sParams.Add("nonce_str", queryorder.nonce_str);
            queryorder.sign = getsign(sParams, key);
            sParams.Add("sign", queryorder.sign);

            //拼接成XML請求數據
            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;
        }
    }
}

 看官網例子：

function onBridgeReady(){
   WeixinJSBridge.invoke(
       'getBrandWCPayRequest', {
           "appId" : "wx2421b1c4370ec43b",     //公衆號名稱，由商戶傳入     
           "timeStamp":" 1395712654",         //時間戳，自1970年以來的秒數     
           "nonceStr" : "e61463f8efa94090b1f366cccfbbb444", //隨機串     
           "package" : "prepay_id=u802345jgfjsdfgsdg888",     
           "signType" : "MD5",         //微信簽名方式:     
           "paySign" : "70EA570631E4BB79628FBCA90534C63FF7FADD89" //微信簽名 
       },
       function(res){     
           if(res.err_msg == "get_brand_wcpay_request:ok" ) {}     // 使用以上方式判斷前端返回,微信團隊鄭重提示：res.err_msg將在用戶支付成功後返回    ok，但並不保證它絕對可靠。 
       }
   ); 
}
if (typeof WeixinJSBridge == "undefined"){
   if( document.addEventListener ){
       document.addEventListener('WeixinJSBridgeReady', onBridgeReady, false);
   }else if (document.attachEvent){
       document.attachEvent('WeixinJSBridgeReady', onBridgeReady); 
       document.attachEvent('onWeixinJSBridgeReady', onBridgeReady);
   }
}else{
   onBridgeReady();
} 

主要是prepay_id和paySign的獲取。類庫tenpay.dll的做用就是獲取這兩個東西的。

大體流程：獲取公衆號的code——》獲取預約單號的openid——》獲取prepay_id。

1.根據本身的業務邏輯生成內部訂單

    protected void btnPay_Click(object sender, EventArgs e)
    {
        if (Fetch.GetUserCookie() == null)
        {
            Response.Redirect("/App/Login.aspx?url=/App/indexPay.aspx");
            return;
        }

        int salePrice = Utility.StrToInt(OrderAmount, 0);
        OnLineOrder onlineOrder = new OnLineOrder();
        onlineOrder.ShareID = 13;
        onlineOrder.OrderID = PayHelper.GetOrderIDByPrefix("WX");

        #region 訂單處理

        if (Fetch.GetUserCookie() == null)
        {
            onlineOrder.OperUserID = 0;
        }
        else
        {
            onlineOrder.OperUserID = Fetch.GetUserCookie().UserID;
        }
        onlineOrder.Accounts = Fetch.GetUserCookie().Accounts;
        onlineOrder.CardTotal = 1;
        onlineOrder.CardTypeID = salePrice / 10; //< 30 ? 1 : salePrice < 60 ? 2 : salePrice < 120 ? 3 : 4;
        onlineOrder.OrderAmount = salePrice;
        onlineOrder.IPAddress = GameRequest.GetUserIP();

        //生成訂單
        Message umsg = treasureFacade.RequestOrder(onlineOrder);
        if (!umsg.Success)
        {
            RenderAlertInfo(true, umsg.Content, 2);
            return;
        }
        #endregion

        //發起微信支付

        Response.Redirect("https://open.weixin.qq.com/connect/oauth2/authorize?appid=你的公衆號appid&redirect_uri=http://你的網站/App/Pay/PayOrder.aspx?showwxpaytitle=1&response_type=code&scope=snsapi_base&state=" + OrderAmount + "_" + onlineOrder.OrderID + "#wechat_redirect");

    }

2.進入公衆號配置網頁受權獲取用戶基本信息

這樣配置後就能夠調用微信的接口獲取到公衆號的code

Response.Redirect("https://open.weixin.qq.com/connect/oauth2/authorize?appid=你的公衆號appid&redirect_uri=http://你的網站/App/Pay/PayOrder.aspx?showwxpaytitle=1&response_type=code&scope=snsapi_base&state=" + OrderAmount + "_" + onlineOrder.OrderID + "#wechat_redirect");

訪問https://open.weixin.qq.com/connect/oauth2/authorize接口，成功後會跳轉到設置的redirect_uri頁面，其中會包含code參數，接下來就到redirect_uri頁面（我這裏就是PayOrder.aspx了）簡單的獲取code參數：

 View Code

上面一句

protected string code = GameRequest.GetQueryString("code");

就獲取到了傳過來的code參數。

而後調用網頁受權接口https://api.weixin.qq.com/sns/oauth2/access_token 獲取openid

這個接口返回的數據是json類型的，使用JavaScriptSerializer類和結構體把openid取出：

    public struct authorization
    {
        public string access_token { get; set; }  //屬性的名字，必須與json格式字符串中的"key"值同樣。
        public string expires_in { get; set; }
        public string refresh_token { get; set; }
        public string openid { get; set; }
        public string scope { get; set; }
    }

            TenpayUtil tenpay = new TenpayUtil();
            string paySignKey = ConfigurationManager.AppSettings["paySignKey"].ToString();
            string AppSecret = ConfigurationManager.AppSettings["AppSecret"].ToString();
            string mch_id = ConfigurationManager.AppSettings["mch_id"].ToString();
            appId = ConfigurationManager.AppSettings["AppId"].ToString();

            string post_data = "appid=" + appId + "&secret=" + AppSecret + "&code=" + code + "&grant_type=authorization_code";
            string requestData = tenpay.PostXmlToUrl(TenpayUtil.getAccess_tokenUrl(), post_data);

            JavaScriptSerializer js = new JavaScriptSerializer();   //實例化一個可以序列化數據的類
            authorization auth = js.Deserialize<authorization>(requestData);    //將json數據轉化爲對象類型並賦值給auth

AppId和AppSecret是公衆號裏面給的，mch_id是經過微信支付申請後微信發郵件給的，paySignKey是本身設置的證書密陰

TenpayUtil.getAccess_tokenUrl()="https://api.weixin.qq.com/sns/oauth2/access_token"

這樣轉化後就能夠獲得openid

order.openid = auth.openid;

終於到重頭戲獲取prepay_id了

            UnifiedOrder order = new UnifiedOrder();
            order.appid = appId;
            order.attach = "vinson";
            order.body = OrderAmount + "拍幣";
            order.device_info = "";
            order.mch_id = mch_id;
            order.nonce_str = TenpayUtil.getNoncestr();
            order.notify_url = "http://你的網站/App/Shop/pay.aspx";
            order.openid = auth.openid;
            order.out_trade_no = OrderID;
            order.trade_type = "JSAPI";
            order.spbill_create_ip = Page.Request.UserHostAddress;
            order.total_fee = int.Parse(OrderAmount) * 100;
            //order.total_fee = 1;

            prepay_id = tenpay.getPrepay_id(order, paySignKey);

對象類型UnifiedOrder方便把多個參數融合一個對象中，看看tenpay.getPrepay_id(order, paySignKey)方法：

        /// <summary>
        /// 獲取prepay_id
        /// </summary>
        public string getPrepay_id(UnifiedOrder order, string key)
        {
            string prepay_id = "";
            string post_data = getUnifiedOrderXml(order, key);
            string request_data = PostXmlToUrl(UnifiedPayUrl, post_data);
            SortedDictionary<string, string> requestXML = GetInfoFromXml(request_data);
            foreach (KeyValuePair<string, string> k in requestXML)
            {
                if (k.Key == "prepay_id")
                {
                    prepay_id = k.Value;
                    break;
                }
            }
            return prepay_id;
        }

接口UnifiedPayUrl="https://api.mch.weixin.qq.com/pay/unifiedorder"

這個接口的參數是xml格式的，返回來的數據也是xml格式的

        /// <summary>
        /// 微信統一下單接口xml參數整理
        /// </summary>
        /// <param name="order">微信支付參數實例</param>
        /// <param name="key">密鑰</param>
        /// <returns></returns>
        protected string getUnifiedOrderXml(UnifiedOrder order, string key)
        {
            string return_string = string.Empty;
            SortedDictionary<string, string> sParams = new SortedDictionary<string, string>();
            sParams.Add("appid", order.appid);
            sParams.Add("attach", order.attach);
            sParams.Add("body", order.body);
            sParams.Add("device_info", order.device_info);
            sParams.Add("mch_id", order.mch_id);
            sParams.Add("nonce_str", order.nonce_str);
            sParams.Add("notify_url", order.notify_url);
            sParams.Add("openid", order.openid);
            sParams.Add("out_trade_no", order.out_trade_no);
            sParams.Add("spbill_create_ip", order.spbill_create_ip);
            sParams.Add("total_fee", order.total_fee.ToString());
            sParams.Add("trade_type", order.trade_type);
            order.sign = getsign(sParams, key);
            sParams.Add("sign", order.sign);

            //拼接成XML請求數據
            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());
            byte[] byteArray = Encoding.UTF8.GetBytes(return_string);
            return_string = Encoding.GetEncoding("GBK").GetString(byteArray);
            return return_string;
            
        }

全部參數準備完畢，就剩下最後的微信簽名paySign了：

            prepay_id = tenpay.getPrepay_id(order, paySignKey);

            timeStamp = TenpayUtil.getTimestamp();
            nonceStr = TenpayUtil.getNoncestr();

            SortedDictionary<string, string> sParams = new SortedDictionary<string, string>();
            sParams.Add("appId", appId);
            sParams.Add("timeStamp", timeStamp);
            sParams.Add("nonceStr", nonceStr);
            sParams.Add("package", "prepay_id=" + prepay_id);
            sParams.Add("signType", "MD5");
            paySign = tenpay.getsign(sParams, paySignKey);

這裏要注意了：appId這些參數的大小寫必定要和js那邊的參數大小寫一致！稍微有所不一樣都會提示「商戶簽名錯誤」。

<script type="text/javascript">
    var appId = "<%=appId %>";
    var timeStamp = "<%=timeStamp %>";
    var nonceStr = "<%=nonceStr %>";
    var prepay_id = "<%=prepay_id %>";
    var paySign = "<%=paySign %>";
    var OrderID="<%=OrderID %>";
    //alert("appId:" + appId + ",timeStamp:" + timeStamp + ",nonceStr:" + nonceStr + ",prepay_id:" + prepay_id + ",paySign:" + paySign);
    //return;
    function onBridgeReady() {
        WeixinJSBridge.invoke(
       'getBrandWCPayRequest', {
           "appId": appId,     //公衆號名稱，由商戶傳入     
           "timeStamp": timeStamp,         //時間戳，自1970年以來的秒數     
           "nonceStr": nonceStr, //隨機串     
           "package": "prepay_id=" + prepay_id,
           "signType": "MD5",         //微信簽名方式:     
           "paySign": paySign //微信簽名 
       },
       function (res) {
           if (res.err_msg == "get_brand_wcpay_request:ok") {
               $(function () {
                   $.ajax({
                       contentType: "application/json",
                       url: "/WS/vinson.asmx/payWeiXin",
                       data: "{OrderID:'" + OrderID + "'}",
                       type: "POST",
                       dataType: "json",
                       success: function (json) {
                           json = eval("(" + json.d + ")");
                           if (json.success == "success") {
                               $("#tip").text("支付成功，正在跳轉......");
                               window.location = "http://你的網站/App/Shop/successful.aspx";
                           }
                           else {
                               $("#tip").text(json.msg);
                               alert(json.msg);
                               window.location = "http://你的網站/App/indexPay.aspx";
                           }
                       },
                       error: function (err, ex) {
                           alert(err.responseText);
                       }
                   });
               })
           }     // 使用以上方式判斷前端返回,微信團隊鄭重提示：res.err_msg將在用戶支付成功後返回    ok，但並不保證它絕對可靠。 
           else {
               alert("交易取消");
               window.location="http://www.你的網站.cn/App/indexPay.aspx";
           }
       }
   );
    }
    if (typeof WeixinJSBridge == "undefined") {
        if (document.addEventListener) {
            document.addEventListener('WeixinJSBridgeReady', onBridgeReady, false);
        } else if (document.attachEvent) {
            document.attachEvent('WeixinJSBridgeReady', onBridgeReady);
            document.attachEvent('onWeixinJSBridgeReady', onBridgeReady);
        }
    } else {
        onBridgeReady();
    } 
</script>

要發起微信支付，還要到公衆號設置支付受權目錄：

一切準備就緒，就能夠真正的發起微信支付了：