在我的应用程序，_collection是一个列表，从中我需要删除所有用户对象不匹配的标准

但是，下面的code得到一个无效的操作在其第二次迭代错误，因为_collection本身已经改变了：

 的foreach（在_collection用户的用户）
{
    如果（！user.IsApproved（））
    {
        _collection.Remove（用户）;
    }
}
 

我可以创建另一个列表的收集和复制他们来回，但后来才知道有非克隆的引用类型的问题，等等。

有没有办法做到上面更优雅比复制_collection到另一另一个列表变量？

  _collection.RemoveAll（用户=＆GT;！user.IsApproved（））;
 

如果你的还是的在2.0：

  _collection.RemoveAll（委托（用户U）{返回u.IsApproved（）;}）;
 

顺便说一句，如果你不想要触摸原始列表，你可以得到的另一个的批准用户提供清单：

  _collection.FindAll（用户=＆GT; user.IsApproved（））;
 

In my application, _collection is a List from which I need to remove all User objects which do not match the criteria.

However, the following code gets an invalid operation error in its second iteration since the _collection itself has been changed:

foreach (User user in _collection)
{
    if (!user.IsApproved())
    {
        _collection.Remove(user);
    }
}

I could create another List collection and copy them back and forth but then I have the issue of non-cloned reference types, etc.

Is there a way to do the above more elegantly than copying _collection to another another List variable?

_collection.RemoveAll(user => !user.IsApproved());

If you're still on 2.0:

_collection.RemoveAll(delegate(User u) { return !u.IsApproved(); });

By the way, if you don't want to touch the original list, you can get another list of approved users with:

_collection.FindAll(user => user.IsApproved());