支付寶的接口調用很不方便，剛做好一個封裝，實現了虛擬交易和實物交易。
解決方案中有三個項目以及ndoc生成的文檔，簡單的序列圖：commonalipay，封裝的支付寶接口。
 testali,asp.net的測試項目
testcommonalipay，nunit的測試項目。
調用方法：
1、引入commonalipay.dll
2、實現支付寶服務接口的方法調用方式：
 alipay ap = new alipay();
        string key = "";//填寫自己的key
        string partner = "";//填寫自己的partner
        standardgoods bp = new standardgoods("trade_create_by_buyer", partner, key, "md5", "卡2", guid.newguid().tostring(), 2.551m, 1, "[email protected]", "[email protected]"
            , "ems", 25.00m, "buyer_pay","1");
           bp.notify_url = "http://203.86.79.185/ali/notify.aspx";
        ap.createstandardtrade("https://www.alipay.com/cooperate/gateway.do", bp, this);上面是通用的調用方式。
下面是只支持虛擬貨物的方式：
 string key = "";//填寫自己的key
        string partner = "";//填寫自己的partner
        alipay ap = new alipay();
        digitalgoods bp = new digitalgoods("create_digital_goods_trade_p", partner, key, "md5", "卡2", guid.newguid().tostring(), 2.551m, 1, "[email protected]", "[email protected]");
        bp.notify_url = "http://203.86.79.185/ali/notify.aspx";
        ap.createdigitaltrade("https://www.alipay.com/cooperate/gateway.do", bp, this);3、實現支付寶通知接口方法的調用（支持虛擬和實物）：
protected void page_load(object sender, eventargs e)
    {
      
        string key = "";//填寫自己的key
        string partner = "";//填寫自己的partner
         alipay ap = new alipay();
         string notifyid = request.form["notify_id"];
         verify v = new verify("notify_verify", partner, notifyid);
        ap.waitsellersendgoods+=new alipay.processnotifyeventhandler(ap_waitsellersendgoods);
        ap.waitbuyerpay += new alipay.processnotifyeventhandler(ap_waitbuyerpay);
        ap.processnotify(this, "https://www.alipay.com/cooperate/gateway.do",key,v, "utf-8");
    }

    void ap_waitbuyerpay(object sender, notifyeventargs e)
    {
        // //加入自己的處理邏輯
        log4net.log.error("wait buyer pay fire");
    }

  
    private void ap_waitsellersendgoods(object sender, notifyeventargs e)
    {
        //加入自己的處理邏輯
        log4net.log.error("waitsellersendgoods fire");
    }支付寶的交易狀態都被定義成了類似名稱的事件。
部分源代碼解析：
1、解析forms集合到notifyeventargs類，因為后面此類的數據要用來做md5sign，所以所有值類型，不能存在初始值，如：int的0等。因此用nullable范型。
   private notifyeventargs parsenotify(namevaluecollection nv, object obj)
        {
            propertyinfo[] propertyinfos = obj.gettype().getproperties(bindingflags.public | bindingflags.instance);

            foreach (propertyinfo pi in propertyinfos)
            {
                string v = nv.get(pi.name.tolower());
                if (v != null)
                {
                    if (pi.propertytype == typeof(string))
                    {

                        pi.setvalue(obj, v, null);

                    }
                    else if (pi.propertytype == typeof(int?))
                    {
                        pi.setvalue(obj, int.parse(v), null);
                    }
                    else if (pi.propertytype == typeof(decimal?))
                    {

                        pi.setvalue(obj, decimal.parse(v), null);
                    }
                    else if (pi.propertytype == typeof(datetime?))
                    {

                        pi.setvalue(obj, datetime.parse(v), null);
                    }
                    else if (pi.propertytype == typeof(bool))
                    {

                        pi.setvalue(obj, bool.parse(v), null);
                    }
                    else
                    {
                        //轉型失敗會拋出異常
                        pi.setvalue(obj, v, null);
                    }
                }

            }
            return (notifyeventargs)obj;

        }
2、從類型中獲取排序后的參數
 /**//// <summary>
        /// 獲取排序后的參數
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        private sortedlist<string,string> getparam(object obj)
        {
           
            propertyinfo[] propertyinfos = obj.gettype().getproperties(bindingflags.public|bindingflags.instance);         
            sortedlist<string, string> sortedlist = new sortedlist<string, string>(stringcomparer.currentcultureignorecase);
            foreach (propertyinfo pi in propertyinfos)
            {

                if (pi.getvalue(obj, null) != null)
                {
                    if (pi.name == "sign" || pi.name == "sign_type")
                    {
                        continue;
                    }
                    sortedlist.add(pi.name.tolower(), pi.getvalue(obj, null).tostring());
                 
                }
            }
            return sortedlist;
                   
        }3、從sortedlist中產生參數
 private string geturlparam(sortedlist<string, string> sortedlist,bool isencode)
        {
            stringbuilder param = new stringbuilder();
            stringbuilder encodeparam = new stringbuilder();
            if (isencode == false)
            {

                foreach (keyvaluepair<string, string> kvp in sortedlist)
                {
                    string t = string.format("{0}={1}", kvp.key, kvp.value);
                    param.append(t + "&");
                }
                return param.tostring().trimend('&');
            }
            else
            {
                foreach (keyvaluepair<string, string> kvp in sortedlist)
                {
                     string et = string.format("{0}={1}", httputility.urlencode(kvp.key), httputility.urlencode(kvp.value));
                     encodeparam.append(et + "&");
                }
                return encodeparam.tostring().trimend('&');
            }
 
        }