Prevent other classes from altering a list in a class

Question

If I have a class that contains, for example, a List and I want other classes to be able to see the list but not set it, I can declare

Answer 1

public class SomeClass()
{
    private List _someList = new List();

    public IList SomeList 
    { 
         get { return _someList.AsReadOnly(); } 
    }
}