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; } }
使用方法如下（针对ID，和Name进行Distinct）
var query = people.DistinctBy(p => new { p.Id, p.Name });
若仅仅针对ID进行distinct：
var query = people.DistinctBy(p => p.Id);
原文：https://www.cnblogs.com/coce/p/14852537.html