使用 Linq 除了不像我想的那样工作 [英] Using Linq Except not Working as I Thought

问题描述

List1 包含项目 { A, B } 和 List2 包含项目 { A, B, C }.

List1 contains items { A, B } and List2 contains items { A, B, C }.

我需要的是返回 { C } 当我使用 Ext Linq 扩展时.相反，我得到了返回 { A, B } 并且如果我在表达式中翻转列表，结果是 { A, B, C }.

What I need is to be returned { C } when I use Except Linq extension. Instead I get returned { A, B } and if I flip the lists around in my expression the result is { A, B, C }.

我是不是误解了例外"的意思?有没有其他扩展我没有看到使用?

Am I misunderstanding the point of Except? Is there another extension I am not seeing to use?

到目前为止，我已经浏览并尝试了许多关于此问题的不同帖子，但都没有成功.

I have looked through and tried a number of different posts on this matter with no success thus far.

var except = List1.Except(List2); //This is the line I have thus far

是的，我正在比较简单的对象.我从未使用过 IEqualityComparer，学习起来很有趣.

Yes I was comparing simple objects. I have never used IEqualityComparer, it was interesting to learn about.

感谢大家的帮助.问题不在于实现比较器.以下链接的博客文章和示例有帮助.

Thanks all for the help. The problem was not implementing the comparer. The linked blog post and example below where helpful.

推荐答案

如果您在列表中存储引用类型，您必须确保有一种方法可以比较对象的相等性.否则将通过比较它们是否引用相同的地址来检查它们.

If you are storing reference types in your list, you have to make sure there is a way to compare the objects for equality. Otherwise they will be checked by comparing if they refer to same address.

您可以实现 IEqualityComparer 并将其作为参数发送到 Except() 函数.这是一个 博客发帖你可能会觉得有帮助.

You can implement IEqualityComparer<T> and send it as a parameter to Except() function. Here's a blog post you may find helpful.

编辑:原始博文链接 已损坏并已在上面替换

edit: the original blog post link was broken and has been replaced above

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