2014-0403

C# List使用District去重复数据

作者: momy 分类: 编程开发 0 Comment »
摘要:C# List使用District去重复数据,包括委托和Lambda方法去重复,需要实现IEqualityComparer接口
class ListDistinctDemo
    {
        static void Main(string[] args)
        {
            List<Person> personList = new List<Person>(){
                new Person(3),//重复数据
                new Person(3),
                new Person(2),
                new Person(1)
            };
            //使用匿名方法
            List<Person> delegateList = personList.Distinct(new Compare<Person>(
                delegate(Person x, Person y)
                {
                    if (null == x || null == y) return false;
                    return x.ID == y.ID;
                })).ToList();
            delegateList.ForEach(s => Console.WriteLine(s.ID));
            //使用 Lambda 表达式
            List<Person> lambdaList = personList.Distinct(new Compare<Person>(
                (x, y) => (null != x && null != y) && (x.ID == y.ID))).ToList();
            lambdaList.ForEach(s => Console.WriteLine(s.ID));
            //排序
            personList.Sort((x, y) => x.ID.CompareTo(y.ID));
            personList.ForEach(s => Console.WriteLine(s.ID));
        }
    }
    public class Person
    {
        public int ID { get; set; }
        public string Name { get; set; }
                              
        public Person(int id)
        {
            this.ID = id;
        }
    }
    public delegate bool EqualsComparer<T>(T x, T y);
    public class Compare<T> : IEqualityComparer<T>
    {
        private EqualsComparer<T> _equalsComparer;
        public Compare(EqualsComparer<T> equalsComparer)
        {
            this._equalsComparer = equalsComparer;
        }
        public bool Equals(T x, T y)
        {
            if (null != this._equalsComparer)
                return this._equalsComparer(x, y);
            else
                return false;
        }
        public int GetHashCode(T obj)
        {
            return obj.ToString().GetHashCode();
        }
    }

废话不多说,直接看代码

标签: IEqualityComparer<T> List C# District Lambda 阅读: 10319
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