隨著微軟的開源，越來越多的項目支持跨平臺，但是各種支付平臺提供的類庫，又老又不支持跨平臺，吐槽下，尤其是微信，還有好多坑，於是ICanPay誕生了，今天就來講ICanPay是什麼，怎麼使用？

ICanPay是一個支持多商戶多種支付方式的跨平臺網關處理類庫，使用ICanPay可以簡化訂單的創建、查詢、退款和接收網關返回的支付通知等操作。

目前支持的支付網關有：支付寶(Alipay)、微信支付(Wechatpay)、銀聯支付(Unionpay)

下麵以支付寶為例，其餘兩種支付，請參考Wiki

1. 配置商戶數據

1.在Startup中添加商戶數據

    services.AddICanPay(a =>
    {
        var gateways = new Gateways();

        var merchant = new Merchant
        {
             AppId = "",
             NotifyUrl = "",
             ReturnUrl = "",
             AlipayPublicKey = "",
             Privatekey = ""
         };

        gateways.Add(new AlipayGateway(merchant));

        return gateways;
    });

2.在Startup中使用ICanPay

    app.UseICanPay();

以上就簡單的完成了對ICanPay的配置操作

2.支付

ICanPay支持多種支付方式，下麵就來講解如何使用

1.獲取支付網關

    private readonly IGateways gateways;

    public YourController(IGateways gateways)
    {
        this.gateways = gateways;
    }

2.創建訂單

    var order = new Order()
    {
        Amount = 0.01,
        OutTradeNo = "訂單號",
        Subject = "測試",
    };

3.設置支付方式

    var gateway = gateways.Get<AlipayGateway>(GatewayTradeType.Web);

4.支付

    gateway.Payment(order);

特殊說明：GatewayTradeType.Barcode支付方式，需要再實現PaymentSucceed和PaymentFailed事件

3.非同步通知

1.獲取支付網關

    private readonly IGateways gateways;

    public NotifyController(IGateways gateways)
    {
        this.gateways = gateways;
    }

2.實現支付通知事件

    PaymentNotify notify = new PaymentNotify(gateways);
    notify.PaymentSucceed += Notify_PaymentSucceed;
    notify.PaymentFailed += Notify_PaymentFailed;
    notify.UnknownGateway += Notify_UnknownGateway;

    private void Notify_PaymentSucceed(object sender, PaymentSucceedEventArgs e)
    {
        // 支付成功時時的處理代碼
        /* 建議添加以下校驗。
         * 1、需要驗證該通知數據中的OutTradeNo是否為商戶系統中創建的訂單號，
         * 2、判斷Amount是否確實為該訂單的實際金額（即商戶訂單創建時的金額），
         */
        if (e.GatewayType == typeof(AlipayGateway))
        {
            var notify = (Notify)e.Notify;
        }
    }

    private void Notify_PaymentFailed(object sender, PaymentFailedEventArgs e)
    {
        // 支付失敗時的處理代碼
    }

    private void Notify_UnknownGateway(object sender, UnknownGatewayEventArgs e)
    {
        // 無法識別支付網關時的處理代碼
    }

3.接收支付通知

    await notify.ReceivedAsync();

4.輔助介面

1.查詢

    var notify = (Notify)gateway.Query(new Auxiliary
    {
            OutTradeNo = "訂單號"
    });

2.撤銷

    var notify = (Notify)gateway.Cancel(new Auxiliary
    {
            OutTradeNo = "訂單號"
    });

3.關閉

    var notify = (Notify)gateway.Close(new Auxiliary
    {
            OutTradeNo = "訂單號"
    });

4.退款

    var notify = (Notify)gateway.Refund(new Auxiliary
    {
            OutTradeNo = "訂單號"，
            RefundAmount = 123,
            OutRefundNo = "退款單號"
    });

5.退款查詢

    var notify = (Notify)gateway.RefundQuery(new Auxiliary
    {
            OutTradeNo = "訂單號"，
            OutRefundNo = "退款單號"
    });

6.對賬單下載

    gateway.BillDownload(new Auxiliary
    {
            BillType = "trade",
            BillDate = "2017-10-31"
    });

以上就簡單的講解瞭如何使用ICanPay,如果有什麼問題，也可以在Github上提問。
項目地址：ICanPay