C# SteamBot - 获取交易报价状态

Question

我在使用此代码时遇到错误：

var offer = Bot.NewTradeOffer(dbSteamId);

    offer.Items.AddMyItem(730, 2, 2611100148);

    if (offer.Items.NewVersion)
    {
        string newOfferId;
        if (offer.SendWithToken(out newOfferId, dbToken, dbMessage))
        {
            Log.Success("Trade offer sent : Offer ID " + newOfferId);
            Bot.TryGetTradeOffer(newOfferId, out offer);
        }
     }

它因错误而崩溃：

ERROR: System.NullReferenceException: Object reference not set to an instance of an object. 
at SteamTrade.TradeOffer.TradeOfferManager.IsOfferValid(Offer offer) in C:\Users\Robertas\Desktop\SteamBot-master\SteamTrade\TradeOffer\TradeOfferManager.cs:line 130
at SteamTrade.TradeOffer.TradeOfferManager.GetOffer(String offerId, TradeOffer& tradeOffer) in C:\Users\Robertas\Desktop\SteamBot-master\SteamTrade\TradeOffer\TradeOfferManager.cs:line 162
at SteamBot.Bot.TryGetTradeOffer(String offerId, TradeOffer& tradeOffer) in C:\Users\Robertas\Desktop\SteamBot-master\SteamBot\Bot.cs:line 331
at SteamBot.TradeOfferUserHandler.SendTradeOffer() in C:\Users\Robertas\Desktop\SteamBot-master\SteamBot\TradeOfferUserHandler.cs:line 81
at SteamBot.TradeOfferUserHandler.OnLoginCompleted() in C:\Users\Robertas\Desktop\SteamBot-master\SteamBot\TradeOfferUserHandler.cs:line 64
at SteamBot.Bot.<HandleSteamMessage>b__5(LoginKeyCallback callback) in C:\Users\Robertas\Desktop\SteamBot-master\SteamBot\Bot.cs:line 476
at SteamKit2.CallbackMsgExtensions.Handle[T](ICallbackMsg msg, Action`1 handler)
at SteamBot.Bot.HandleSteamMessage(ICallbackMsg msg) in C:\Users\Robertas\Desktop\SteamBot-master\SteamBot\Bot.cs:line 458
at SteamBot.Bot.BackgroundWorkerOnDoWork(Object sender, DoWorkEventArgs doWorkEventArgs) in C:\Users\Robertas\Desktop\SteamBot-master\SteamBot\Bot.cs:line 941

有什么想法吗？也许你知道检查交易报价状态的不同方法？请分享您的想法。谢谢！

已编辑：

public bool GetOffer(string offerId, out TradeOffer tradeOffer)
{
    tradeOffer = null;
    var resp = webApi.GetTradeOffer(offerId);
    if (resp != null)
    {
        if (IsOfferValid(resp.Offer))
        {
            tradeOffer = new TradeOffer(session, resp.Offer);
            return true;
        }
        else
        {
            //todo: log steam api is giving us invalid offers.
            Console.WriteLine("Offer returned from steam api is not valid : " + resp.Offer.TradeOfferId);
        }
    }
    return false;
}

resp.Offer 为空。怎么可能为空？我可以提到当机器人发送到我的帐户时一切正常，但是当它发送到其他帐户时，它崩溃了。

已编辑#2：

好的，我发现了错误。得到回应是问题。当我调用这个（http://api.steampowered.com/IEconService/GetTradeOffer/v1/?key=48B9FCE3FE8A74ADDA29174BFD47441B&tradeofferid=530787948&language=en_us）时：

{
"response": {

}

}

当我调用它时(http://api.steampowered.com/IEconService/GetTradeOffer/v1/?key=48B9FCE3FE8A74ADDA29174BFD47441B&tradeofferid=530796219&language=en_us):

{
"response": {
    "offer": {
        "tradeofferid": "530796219",
        "accountid_other": 213128749,
        "message": "Security Code: HqaMyUDN",
        "expiration_time": 1435675048,
        "trade_offer_state": 2,
        "items_to_receive": [
            {
                "appid": "730",
                "contextid": "2",
                "assetid": "2275856684",
                "classid": "310776767",
                "instanceid": "0",
                "amount": "1",
                "missing": false
            }
        ]
        ,
        "is_our_offer": false,
        "time_created": 1434465448,
        "time_updated": 1434465448,
        "from_real_time_trade": false
    },...

知道为什么一个响应是空的，而另一个是正常的吗？

Answer 1

看来您正在使用 SteamBot library. Since its source code is readily available, take a look at the source code for the GetTradeOffer method, found here: TradeOfferWebApi source

很明显，从此方法接收到非空响应并不能保证它包含有效的报价对象。您的支票 resp.Offer，因此，应该首先验证它不为空：

    if (resp != null)
    {
        if (resp.Offer != null && IsOfferValid(resp.Offer))

至于确定为什么它不为空：将源代码抓取到 SteamBot，运行您的应用程序 + 调试器中的 SteamBot 项目，然后进入方法.根据 GetTradeOffer 方法的源代码，它很可能会引发异常。

考虑到代码中 'todo' 条评论的数量，该库似乎仍处于开发中，因此运行 SteamBot 源代码可能有助于调试目的（您可以轻松修改源代码以实际将异常记录到对您有用的目的地）。

编辑（响应 OP 的编辑 #2）：从文档到 Steam's IEconService API，一个帐户只能检索关于该帐户的优惠信息。可能的解释是，要么您传递了无效的优惠 ID（您可能已经排除了），要么您的应用所在的帐户运行ning 无权查看此优惠。

C# SteamBot - 获取交易报价状态

C# SteamBot - Get trade offer state

c#

steambot