扩展Linq的Distinct方法动态根据条件进行筛选

Person1: Id=1, Name="Test1"

Person2: Id=1, Name="Test1"

Person3: Id=2, Name="Test2"

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;

        }

    }

}

var query = people.DistinctBy(p => new { p.Id, p.Name });

var query = people.DistinctBy(p => p.Id);

List<Person> distinctPeople = allPeople

  .GroupBy(p => new {p.Id, p.Name} )

  .Select(g => g.First())

  .ToList();