How to use this LINQ with multiple "Where"?

Question

Say I have this structure:

public class Car
{
   public string Name;
   public IList<Tire> Tires;
}

public class Tire
{
   public string Name;
   public int Size;
}

I want a query to return all Cars that have Tires with size 40.

I am thinking this way, what am I missing?

Cars.Where(x => x.Tires.Where(y => y.Size == 40));

This code throws this error: "Cannot convert lambda expression to delegate type 'System.Func' because some of the return types in the block are not implicitly convertible to the delegate return type"

Answer 1

You want

Cars.Where(x => x.Tires.Any(y => y.Size == 40));

or

Cars.Where(x => x.Tires.All(y => y.Size == 40));

Depending on the requirement.

Your version won't work because the outer lambda is actually returning an IEnumerable<Tire>, whereas it needs to be a bool.

Answer 2

You should use Any instead.

Cars.Where(x => x.Tires.Any(y => y.Size == 40));