Encapsulating C# List through method call

Question

In C# when I want to encapsulate a List I place it inside of a class and throw some helper methods in there with it. However, what I have noticed is that whenever I want to iterate over the list of items I just return the list. Simple. However, what is bad about this is that I am unable to tell if the list has been modified by some method gone wrong.

So this is what I have been doing:

class Animals
{
    private List<Dog> _dogs;

    public List<Dog> Dogs
    {
        get { return _dogs; }
    }

}

To conteract this I thought of doing:

class Animals
{
    private List<Dog> _dogs;

    public Dog GetDog(int dogid)
    {
        return _dogs[dogid];
    }

    public int Count
    {
        get { return _dogs.Count; }
    }
}

My real issue with this method lies in the fact that every single time I want an item from the list, a method must be called. This means that if I want to iterate over the list, I must setup a loop to go for Animals.Count number of times calling Animals.GetDog(i) every iteration.

Is this going to affect my program? Is there a more suitable way of accomplishing the same thing?

I've had a look at ways of encapsulating Lists, but they seem quite intricate. My main aim is to not expose _dogs list to anything outside of the class.

Answer 1

You can use an IEnumerable to encapsulate the list quite easily:

public IEnumerable<Dog> GetDogs()
{
    foreach (Dog dog in _dogs)
    {
        yield return dog;
    }
}

This allows you to enumerate the list from outside the class, but not have access to the underlying list.

//Outside Animals class
foreach (Dog dog in animalObj.GetDogs())
{
    //do stuff
}