Linq选择子对象具有匹配子对象的父对象 [英] Linq to Select Parent Objects Where Child Objects Have a Matching Child Object

问题描述

我该如何编写LINQ语句来选择在其集合中具有匹配子对象的父对象?这是示例类.

How would I go about writing a LINQ statement that selects the parent objects that have a matching child object in it's collection? Here's example classes.

class Parent {
    int ID { get; set; }
    string Name { get; set; }
    List<Child> Children { get; set; }
}

class Child {
    int ID { get; set; }
    string Name { get; set; }
    string Nickname { get; set; }
}

在上面的示例中，我想返回包含一个带有特定昵称的孩子的所有父母.

In the example above, I would like to return all of the parents that contain a child with a specific nickname.

推荐答案

这是直接的Linq-to-Objects:

This is straightfoward Linq-to-Objects:

listOfParents.Where(p => p.Children.Contains(childObjectToMatch))

对于Linq-to-Entities，如果未将子对象作为实体跟踪，则可能需要在子对象标识符字段上进行匹配:

For Linq-to-Entities, if the child object isn't tracked as an entity you might need to match on the child object identifier field:

int childObjectIdToMatch = childObjectToMatch.ID;
dbContext.Parents.Where(p => p.Children.Any(c => c.ID == childObjectIdToMatch));

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