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  • List泛型类的方法及使用

    static void Main(string[] args)
    {
    List<Customer> custs = new List<Customer>();
    custs.Add(new Customer() { ID = 1 });
    custs.Add(new Customer() { ID = 5 });

    custs.First(new Func<Customer, bool>(delegate(Customer x) { return x.ID == 5; }));
    custs.First(new Func<Customer, bool>((Customer x) => x.ID == 5));
    custs.First(delegate(Customer x) { return x.ID == 5; });
    custs.First((Customer x) => x.ID == 5);
    custs.First(x => x.ID == 5);
    custs.First(Customer.Test);
    List<Customer> newCusts = custs.Where(x => x.ID == 5).ToList();//找到集合中满足指定条件的元素
    int sum = custs.Sum(x => x.ID);//计算和
    List<Customer> ofType = custs.OfType<Customer>().ToList();//根据指定类型,筛选集合中的元素
    List<int> select = custs.Select(x => x.ID + 1).ToList();//将集合中的每个元素投影的新集合中
    List<string> selectMany = custs.SelectMany(x => new List<string>() { "id:", x.ID.ToString() }).ToList();//将序列的每个元素投影到一个序列中,最终把所有的序列合并

    List<ulong> select= custs.ConvertAll(item => Convert.ToUInt64(item));
    //LINQ
    sum= custs.Where(x => x.ID != 10).Sum(x => x.ID);
    sum = (from v in custs where v.ID != 1 select v).Sum(x => x.ID);

    }

    class Customer
    {
    public int ID { get; set; }
    public static bool Test(Customer x)
    {
    return x.ID == 5;
    }
    }

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  • 原文地址:https://www.cnblogs.com/liuslayer/p/4981603.html
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