获得从IEnumerable非不同的元素 [英] Get Non-Distinct elements from an IEnumerable

问题描述

我有一个叫Item类。项目有一个名为ItemCode一个标识符属性，它是一个字符串。我想获得在项目列表中的所有非重复的项目列表

I have a class called Item. Item has an identifier property called ItemCode which is a string. I would like to get a list of all non-distinct Items in a list of Items.

例如：

List<Item> itemList = new List<Item>()
{
   new Item("code1", "description1"),
   new Item("code2", "description2"),
   new Item("code2", "description3"),
};

我要包含底部两个条目列表

I want a list containing the bottom two entries

如果我用

var distinctItems = itemsList.Distinct();

我得到不同的项目清单，这是伟大的，但我想那几乎相反。我可以从原来的名单中减去鲜明的名单，但将不包含所有重复，每次只是一个实例。

I get the list of distinct items which is great, but I want almost the opposite of that. I could subtract the the distinct list from the original list but that wouldn't contain ALL repeats, just one instance of each.

我有一出戏，可以' W图出优雅的解决方案。任何指针或帮助将非常感激。谢谢！

I've had a play and can't figure out an elegant solution. Any pointers or help would be much appreciated. Thanks!

我有3.5这样LINQ提供

I have 3.5 so LINQ is available

推荐答案

我的采取：

var distinctItems = 
    from list in itemsList
    group list by list.ItemCode into grouped
    where grouped.Count() > 1
    select grouped;

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