代码

    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();

        }

    }