List 去除重复



// 扩展IEnumerable<T>

static class ExternEnumerable {

        public static IEnumerable<TSource> DistinctBy<TSource, TKey>  (this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)

        {

            HashSet<TKey> seenKeys = new HashSet<TKey>();

            foreach (TSource element in source)

            {

                if (seenKeys.Add(keySelector(element)))

                {

                    yield return element;

                }

            }

        }

    }

     

    // 筛选去重调用

     IEnumerable<User> ie = list; // 先转换为IEnumerable接口类型

     ie=ie.DistinctBy<User,string>(u=>u.DatasName+"|"+u.DatasType+"|"+u.DatasValue);