How to filter list with objects in C#?

Question

I have a class House, and I create a List<House>with some new Houses. Now I would like to filter my List' where the Name of the House equals"House 1"`.

How should I handle this situation?

I tried houses.FindAll("House 1"); but this showed the error:

Argument 1: cannot convert from 'string' to System.Predicate <"App.Page1.House">

class House
    {
        public House(string name, string location)
        {
            this.Name = name;
            this.Location = location;
        }

        public string Name { private set; get; }
        public string Location { private set; get; }
    };

    //TODO: fill this with data from the database
    List<House> houses= new List<House>
    {
        new House("House 1", "Location 1"),
        new House("House 2", "Location 4"),
        new House("House 3", "Location 3"),
        new House("House 4", "Location 2")
    };

Answer 1

The problem you are having is that you have to give FindAll a predicate. You can do that with a lambda

List<House> houseOnes = houses.FindAll(house => house.Name == "House 1");

Basically you have to tell it what you want to compare to for each item. In this case you compare the Name property to the string value you are interested in.

Another alternative is to use Linq

List<House> houseOnes = houses.Where(house => house.Name == "House 1").ToList();

Note here you have to call ToList in order to get a list. Without that you'd have an IEnumerabl<House> and it wouldn't actually do the comparisons until you iterated it (which the ToList does). This is known as deferred execution and if your original houses list changed before you iterated it you could get different result, which may or may not be desirable. By calling ToList you ensure that your results will reflect the state of your list when you make that call.

Answer 2

Use Linq:

List<House> houseOnes = houses.Where(house => house.Name == "House 1").ToList();

or if there is only 1 you hope to find

House houseOne = houses.SingleOrDefault(house => house.Name == "House 1");

and check the result for null to make sure you found it.