How do I create a Null Object in C#

Question

Martin Fowler\'s Refactoring discusses creating Null Objects to avoid lots of

if (myObject == null)

tests. What is the right way to do th

Answer 1

The point of the Null Object pattern is that it doesn't require a null check to prevent a crash or error.

For example if you tried to perform an operation on the Species property and it was null - it would cause an error.

So, you shouldn't need an isNull method, just return something in the getter that won't cause the app to crash/error e.g.:

public class Animal
{
    public virtual string Name { get; set; }
    public virtual string Species { get; set; }
}

public sealed class NullAnimal : Animal
{
    public override string Name
    {
        get{ return string.Empty; }
        set { ; }
    }
    public override string Species
    {
        get { return string.Empty; }
        set { ; }
    }
}