如果有一些东西在Distinct查询中被抛出，您可能需要查看MoreLinq并使用DistinctBy操作符并根据id选择不同的对象。

var distinct = items.DistinctBy( i => i.Id );

var distinctItems = items.Distinct();

为了只匹配某些属性，可以创建一个自定义的相等比较器，例如:

class DistinctItemComparer : IEqualityComparer<Item> {

    public bool Equals(Item x, Item y) {
        return x.Id == y.Id &&
            x.Name == y.Name &&
            x.Code == y.Code &&
            x.Price == y.Price;
    }

    public int GetHashCode(Item obj) {
        return obj.Id.GetHashCode() ^
            obj.Name.GetHashCode() ^
            obj.Code.GetHashCode() ^
            obj.Price.GetHashCode();
    }
}

然后这样使用它:

var distinctItems = items.Distinct(new DistinctItemComparer());

你有三个选项来删除列表中的重复项:

Use a a custom equality comparer and then use Distinct(new DistinctItemComparer()) as @Christian Hayter mentioned. Use GroupBy, but please note in GroupBy you should Group by all of the columns because if you just group by Id it doesn't remove duplicate items always. For example consider the following example: List<Item> a = new List<Item> { new Item {Id = 1, Name = "Item1", Code = "IT00001", Price = 100}, new Item {Id = 2, Name = "Item2", Code = "IT00002", Price = 200}, new Item {Id = 3, Name = "Item3", Code = "IT00003", Price = 150}, new Item {Id = 1, Name = "Item1", Code = "IT00001", Price = 100}, new Item {Id = 3, Name = "Item3", Code = "IT00003", Price = 150}, new Item {Id = 3, Name = "Item3", Code = "IT00004", Price = 250} }; var distinctItems = a.GroupBy(x => x.Id).Select(y => y.First()); The result for this grouping will be: {Id = 1, Name = "Item1", Code = "IT00001", Price = 100} {Id = 2, Name = "Item2", Code = "IT00002", Price = 200} {Id = 3, Name = "Item3", Code = "IT00003", Price = 150} Which is incorrect because it considers {Id = 3, Name = "Item3", Code = "IT00004", Price = 250} as duplicate. So the correct query would be: var distinctItems = a.GroupBy(c => new { c.Id , c.Name , c.Code , c.Price}) .Select(c => c.First()).ToList(); 3.Override Equal and GetHashCode in item class: public class Item { public int Id { get; set; } public string Name { get; set; } public string Code { get; set; } public int Price { get; set; } public override bool Equals(object obj) { if (!(obj is Item)) return false; Item p = (Item)obj; return (p.Id == Id && p.Name == Name && p.Code == Code && p.Price == Price); } public override int GetHashCode() { return String.Format("{0}|{1}|{2}|{3}", Id, Name, Code, Price).GetHashCode(); } } Then you can use it like this: var distinctItems = a.Distinct();

当你不想写IEqualityComparer时，你可以试试下面的方法。

 class Program
{

    private static void Main(string[] args)
    {

        var items = new List<Item>();
        items.Add(new Item {Id = 1, Name = "Item1"});
        items.Add(new Item {Id = 2, Name = "Item2"});
        items.Add(new Item {Id = 3, Name = "Item3"});

        //Duplicate item
        items.Add(new Item {Id = 4, Name = "Item4"});
        //Duplicate item
        items.Add(new Item {Id = 2, Name = "Item2"});

        items.Add(new Item {Id = 3, Name = "Item3"});

        var res = items.Select(i => new {i.Id, i.Name})
            .Distinct().Select(x => new Item {Id = x.Id, Name = x.Name}).ToList();

        // now res contains distinct records
    }



}


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

    public string Name { get; set; }
}

试试这个扩展方法。希望这能有所帮助。

public static class DistinctHelper
{
    public static IEnumerable<TSource> DistinctBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
    {
        var identifiedKeys = new HashSet<TKey>();
        return source.Where(element => identifiedKeys.Add(keySelector(element)));
    }
}

用法:

var outputList = sourceList.DistinctBy(x => x.TargetProperty);

var distinctItems = items.GroupBy(x => x.Id).Select(y => y.First());