c# list對象集合 去重

新建一個類，實現IEqualityComparer接口。注意GetHashCode方法的實現，只有HashCode相同才會去比較

    public class Compare:IEqualityComparer<Student>
    {
        public bool Equals(Student x,Student y)
        {
            return x.Id == y.Id;//可以自定義去重規則，此處將Id相同的就作為重復記錄，不管學生的愛好是什么
        }
        public int GetHashCode(Student obj)
        {
            return obj.Id.GetHashCode();
        }
    }

調用：list.Distinct(new Compare()).ToList().ForEach(s => Console.WriteLine(s.ToString()));


列：

    /// <summary>
    /// list對象去重
    /// </summary>
    public class Compare : IEqualityComparer<HistoryStatisticsDTO>
    {
        /// <summary>
        /// 
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns></returns>
        public bool Equals(HistoryStatisticsDTO x, HistoryStatisticsDTO y)
        {
            if (x == null || y == null)
                return false;
            if (x.CaseNumId == x.CaseNumId)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public int GetHashCode(HistoryStatisticsDTO obj)
        {
            if (obj == null)
            {
                return 0;
            }
            else
            {
                return obj.CaseNumId.GetHashCode();
            } 
        }
    }

調用： var list=historyStatistics.Distinct(new Compare()).ToList();