CODEWITHSUNDEEP
c#linqlambda
NoughT
NoughT

Reputation: 673

Group by using inner property in a list using Lambda expression

I have a list that contain following type of objects 

public class A {

    public List<B> B {get;set;}

}

The B class state as follows.

public class B {

    public List <C> C { get;set;}
}

The C class state as follows.

public class C { 

    public int Id { get ; set ;}
    public string Name  { get; set;} 
}

Can someone point me how can I group above list by Name property in C class.

Upvotes: 0

Views: 1388

Answers (1)

Bradley Uffner
Bradley Uffner

Reputation: 16991

var results = a.SelectMany(a1 => a1.B.SelectMany(b1 => b1.C)
              .GroupBy(g => g.Name)
              .Select(g => new { Name = g.Key, Count = g.Count() }));

It should return a list of objects containing a Name property for each unique name found, along with a Count property specifying how many of that Name were grouped.

The nested calls to SelectMany will flatten the object hierarchy, the GroupBy will create the grouping on the Name property. Finally, a new anonymous type List is returned though the Select and is populated with properties from the group, with g.Key being the value the grouping was based on (C.Name).

A Fiddle can be found Here (Provided by @chadalavada harish)

Upvotes: 2

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