Question

doc = GetSecureXDocument（＆＃34; https://www.predictit.org/api/marketdata/all＆＃34;）;

            List <MarketContract> contracts = doc.Root.Element("Markets").Elements("MarketData").Elements("Contracts").Elements("MarketContract").Select(x => new MarketContract
        {
            //ID = int.Parse((string)x.Attribute("ID")),
            URL = (string)x.Attribute("URL"),
            Name = (string)x.Attribute("Name"),
            LongName = (string)x.Attribute("LongName"),
            ShortName = (string)x.Attribute("ShortName"),
            TickerSymbol = (string)x.Attribute("TickerSymbol"),
            Status = (string)x.Attribute("Status"),
            /*BestBuyNoCostInCents = int.Parse((string)x.Attribute("BestBuyNoCost")),
            BestBuyYesCostInCents = int.Parse((string)x.Attribute("BestBuyYesCost")),
            BestSellNoCostInCents = int.Parse((string)x.Attribute("BestSellNoCost")),
            BestSellYesCostInCents = int.Parse((string)x.Attribute("BestSellYesCost"))*/
        }).ToList();

注释掉的部分抛出nullargumentexceptions，当打印URL，Name，LongName等的值时，它们全部为零。

这里＆＃39; x＆＃39;的价值在跑步期间在lambda中：

    <MarketContract>
  <ID>3414</ID>
  <DateEnd>N/A</DateEnd>
  <Image>https://az620379.vo.msecnd.net/images/Contracts/small_f6d2f26b-8055-45a3-872f-0796dc47e238.png</Image>
  <URL>https://www.predictit.org/Contract/3414/Will-a-Democratic-candidate-win-the-2017-Virginia-gubernatorial-race</URL>
  <Name>Democratic</Name>
  <LongName>Will a Democratic candidate win the 2017 Virginia gubernatorial race?</LongName>
  <ShortName>Democratic</ShortName>
  <TickerSymbol>DEM.VAGOV17</TickerSymbol>
  <Status>Open</Status>
  <LastTradePrice>0.75</LastTradePrice>
  <BestBuyYesCost>0.78</BestBuyYesCost>
  <BestBuyNoCost>0.26</BestBuyNoCost>
  <BestSellYesCost>0.74</BestSellYesCost>
  <BestSellNoCost>0.22</BestSellNoCost>
  <LastClosePrice>0.75</LastClosePrice>
</MarketContract>

这是我第一次处理XML，如果有人可以提供帮助，那将非常感谢！

Answer 1

这些是元素，而不是属性。

属性是开始标记内的name="value"对。

XAttribute null即使它存在？

1 个答案: