使用LINQ，在另一个对象列表中选择对象列表 [英] Using LINQ, select list of objects inside another list of objects

问题描述

public class ClassA
{
     public string MyString {get; set;}
}

public class ClassB
{
     public List<ClassA> MyObjects {get; set;}
}

List<ClassB> classBList = new List<ClassB>();
var results = (from i in classBList select i.MyObjects).Distinct();

我想要一个classBList中所有ClassA对象的明确列表.我如何使用 LINQ 来解决这个问题?我正在考虑嵌套查询，但还不太清楚.任何帮助都非常感谢.

I want a distinct list of all the ClassA objects in the classBList. How do I go about this using LINQ? I'm thinking about a nested query, but couldn't quite figure it out. Any help is very appreciated.

推荐答案

您正在尝试为原始列表中的每个ClassB对象选择多个结果对象.

You're trying to select multiple result objects for each ClassB object in the original list.

因此，您正在寻找 SelectMany扩展方法:

Therefore, you're looking for the SelectMany extension method:

var results = classBList.SelectMany(b => b.MyObjects).Distinct();

如果要使用查询表达式，则需要使用两个from子句:

If you want to use query expressions, you'll need to use two from clauses:

var results = (from b in classBList from a in b.MyObjects select a).Distinct();

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