自定义扩展LINQ通用的Distinct规则

public class EqualityComparer<T, V> : IEqualityComparer<T>
  {
        private readonly Func<T, V> _selector;

        public EqualityComparer(Func<T, V> selector)
        {
            _selector = selector;
        }

        public bool Equals([AllowNull] T x, [AllowNull] T y)
        {
            return EqualityComparer<V>.Default.Equals(_selector(x), _selector(y));
        }

        public int GetHashCode([DisallowNull] T obj)
        {
            return EqualityComparer<V>.Default.GetHashCode(_selector(obj));
        }
    }

public static class LinqExtentions
    {
        public static IEnumerable<T> Distinct<T, V>(this IEnumerable<T> source, Func<T, V> selector)
        {
            return source.Distinct(new EqualityComparer<T, V>(selector));
        }
    }

public class Item
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }

...

IEnumerable<Item> items = new List<Item>();
items = items.Distinct(x => x.Id);