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关于在嵌套类中搜索记录的问题。这是我的代码的精简版。希望它解释得足够多！我正在使用 Visual Web Developer 2010 Express。

班级

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

namespace API
{
    public class Fixture
    {
        public int ID { get; set; }
        public string Description { get; set; }
        public List<FixturesMarketData> FixturesMarketData;

        public Fixture()
        {
            FixturesMarketData = new List<FixturesMarketData>();
        }

        public void AddMarket(int _fixtureID, int _marketID, string _MarketName)
        {
            FixturesMarketData.Add(new FixturesMarketData ( _fixtureID, _marketID, _MarketName ));
        }

        public string ListMarkets()
        {
            string strReturn="";
            foreach (var item in FixturesMarketData)
             {
                strReturn = strReturn + "<br />" + item.marketDescription + " - " + item.marketID + " - " + item.fixtureID;
            }
            return strReturn;
        }
    }

    public class FixturesMarketData
    {
        public int fixtureID { get; set; }
        public int marketID { get; set; }
        public string marketDescription { get; set; }

        public FixturesMarketData(int _mdfixtureID, int _mdmarketID, string _mdmarketDescription)
        {
            fixtureID = _mdfixtureID;
            marketID = _mdmarketID;
            marketDescription = _mdmarketDescription;
        }
    }
}

主要代码

_fixtures = new List<Fixture>();
_fixtures.Add(new Fixture { ID = 1234, Description = 'This is a test' });

int index = _fixtures.FindIndex(Fixture => Fixture.ID.Equals(1234));
_fixtures[index].AddMarket(1234, 5678, 'This is a test market');
AddToOutputString(_fixtures[index].ListMarkets());

所以基本上这会导致：

ID= 1234;
Description=This is a test;
FixturesMarketData
FixtureID=1234;
MarketID=5678;
marketDescription=This is a test market;

如何在 FixturesMarketData 上查找市场 id 等于 5678 的位置？

我可以这样做：

var index=-1;
            foreach (var item in _fixtures)
            {
                index = item.FixturesMarketData.FindIndex(entry => entry.marketID.Equals(_marketId));
                if(index!=-1)
                {
                    break;
                }
            }

但我猜肯定有办法以 Lambda Find 风格做到这一点

谢谢！

4

1 回答 1

1 
var enumerable=_fixtures.Where(x=>x.FixturesMarketData.Any(x=>x.marketId==5678));

现在，如果您希望找到许多这样的固定装置，您可以做

enumerable.ToList();

如果你只想要第一个

enumerable.FirstOrDefault();

如果只能找到一个夹具，那么

enumerable.SingleOrDefault();

注意：这里默认意味着如果没有找到返回NULL，否则将抛出错误

于 2012-06-24T10:30:18.197 回答