CODEWITHSUNDEEP
c#linq
olf
olf

Reputation: 872

Use LINQ to get objects with properties = another objects property

Having the following pseudo code:

    class Foo
    {
        public int id { get; set; }
        public string info { get; set; }
    }

    class Bar
    {
        public int id { get; set; }
        public int FooId { get; set; }
        public string moreInfo { get; set; }
    }

    IList<Foo> foos = new List<Foo>();
    foos.Add(new Foo() { id = 1, info = "first!" });
    foos.Add(new Foo() { id = 2, info = "second!" });
    foos.Add(new Foo() { id = 3, info = "third!" });


    IList<Bar> bars = new List<Bar>();
    bars.Add(new Bar() { id = 1, FooId = 1, moreInfo = "Something" });
    bars.Add(new Bar() { id = 2, FooId = 1, moreInfo = "else" });
    bars.Add(new Bar() { id = 3, FooId = 2, moreInfo = "here" });
    bars.Add(new Bar() { id = 4, FooId = 6, moreInfo = "and" });
    bars.Add(new Bar() { id = 5, FooId = 7, moreInfo = "here as well" });

    var returnValue = select bar from bars
                        where bar.FooId IN foos.Id

What I want to achieve is a list (my returnValue) to contain the bars with id 1, 2 and 3 as their FooId is in the list of foos. How can I get that?

Upvotes: 1

Views: 98

Answers (3)

Christos
Christos

Reputation: 53958

You could try something like this:

var filteredBars = bars.Join(foos, x=>x.FooId, y=>y.id, (x, y) => x);

Upvotes: 3

Grundy
Grundy

Reputation: 13380

you can use join clause like this

from bar in bars
join foo in foos on bar.FoorId equals foo.id
select bar

Upvotes: 3

Janne Matikainen
Janne Matikainen

Reputation: 5121

var returnValue = bars.Where(b => foos.Select(f => f.Id).Contains(b.FooId);

Or

var returnValue = from b in bars
                  join f in foos on b.FooId equals f.Id
                  select b;

Upvotes: 4

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