Use LINQ where list of items contains any component in a list of components

Question

Using LINQ, how can I find a list of items where it's list of components contains a component from another list of components?

Structure:

class Item
{
    public List<Component> Components {get;set;}
}

class Component
{
    public string Name {get;set;}
}

Example:

var components = new List<string> { "C1", "C2" , "C3" }
var items = new List<Item>
{
    new Item("IT1")
    {
        Components = new List<Component> { "C1", "C4","C5" }                    
    },
    new Item("IT2")
    {
        Components = new List<Component> { "C6", "C7","C8" }
    },
    new Item("IT3")
    {
        Components = new List<Component> { "C2", "C0","C9" }
    }
} 

The output will returns items IT1 and IT3.

I tried the following:

items
    .Select(i => i.Components)
    .Where(c => components.Contains(c.Any(x => x.Name.ToString()));

I am getting the following error:

Cannot convert lambda expression to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type

Answer 1

It should be the other way around: first the Any and then the Contains . You would like to get all items that have any of there components contained in the components list.

Also don't use the Select if you'd like to get a list of Item back:

var result = items.Where(i => i.Components.Any(c => components.Contains(c.Name)));

Answer 2

It because Any expects boolean value, but you return string: x.Name.ToString .

You can check intersection of two sequences in you case:

items.Where(x => x.Components.Intersect(components).Any())

Intersect will return non-empty sequence, if both item.Components and components contain same elements. Then Any without parameters will return true , if the sequence is non-empty.