通过嵌套列表进行OrderBy列表 [英] OrderBy list by a nested list

问题描述

我有一个objectA列表，每个列表都包含另一个objectB列表.我正在尝试使用(int)ID对每个objectB列表进行排序:

I have a objectA list, each one contain an another objectB list. I'm trying to OrderBy each objectB list with an (int) Id :

var sorted = objectA.OrderBy(a => a.ObjectB.OrderBy(b => b.Id)).ToList();

当然，这是行不通的.有人有建议吗?

Of course, this doesn't work. Someone have an advice ?

推荐答案

如果你想对每个 ObjectB 列表进行排序(即修改它)，那么只需使用 Comparison<T> 代表:

If you want to sort each ObjectB list in place (i.e. modify it), then simply use the List<T>.Sort method. You will need to specify a custom Comparison<T> delegate:

foreach (var a in objectA)
{
   a.ObjectB.Sort((x, y) => x.Id - y.Id)
}

如果 objectA 是 List< ObjectA> ，则可以使用

If objectA is a List<ObjectA>, then you can use the ForEach method and pass a delegate:

objectA.ForEach(a => a.ObjectB.Sort((x, y) => x.Id - y.Id));

如果您不想修改原始的 ObjectA 实例，则必须将每个 ObjectA 实例投影到一个新实例中(通过克隆它)，然后分配排序后的 ObjectB 列表.看起来像(假设所有属性都有公共设置器):

If you don't want to modify your original ObjectA instances, then you will have to project each ObjectA instance into a new instance (by cloning it) and then assign sorted ObjectB lists. It would look something like (presuming that all properties have public setters):

var newList = objectA
    .Select(x => new ObjectA()
    {
        Id = x.Id,
        SomethingElse = x.SomethingElse,
        ObjectB = x.ObjectB.OrderBy(b => b.Id).ToList()
    })
    .ToList();

这篇关于通过嵌套列表进行OrderBy列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！