CODEWITHSUNDEEP
c#
proseidon
proseidon

Reputation: 2305

Finding a list item within a list item

I'm a bit confused on how this works.

class TestClass
{
    public int ID {get;set;}
    public List<Stuff> StuffList {get; set;}
}
class Stuff
{
    public int ID {get;set;}
    public string Description {get;set;}
}

So each TestClass has a list of Stuff in them. What I want to do is find a TestClass that contains any Stuff with an ID of 0

List<TestClass> TestList = RetrieveAllTestLists();
//Pseudocode:
//
// Find all TestClass in TestList that contain a Stuff with ID == 0;

I've tried this but it didn't work:

List<TestClass> TestList = RetrieveAllTestLists().Where(x=> x.StuffList.Where(y=> y.ID == 0)).ToList();

Can anyone explain to me what I did wrong?

Upvotes: 3

Views: 86

Answers (2)

pierroz
pierroz

Reputation: 7870

List<TestClass> TestList = RetrieveAllTestLists().Where(x=> x.StuffList.Any(y=> y.ID == 0)).ToList();

Any() means that at least for one element or the IEnumerable, the predicate given in parameter returns true

Upvotes: 0

Zbigniew
Zbigniew

Reputation: 27594

You can use Any:

List<TestClass> TestList = RetrieveAllTestLists().
                           Where(x => x.StuffList.Any(y=> y.ID == 0)).ToList();

Basicaly Where will select all rows which satisfies condition (those returning true), but in this place you have another Where. Any will return true if there were any row fulfilling given condition.

Upvotes: 5

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