A null object cast to int causes NullReferenceException?

Question

I have the following generic code:

public V put(K key, V value){
        Object o = doOp(ClusterOperation.CONCURRENT_MAP_PUT, key, value);           
        return (V)o;
}

The thing is, the Object o can be null. When I work with objects like String it is ok to return null cast to String. But when V represents int, then null cast to int throws NullReferenceException.

Is there any solution that is generic enough and handles int's?

Thanks

Answer 1

Use the default keyword:

if(o == null)
  return default(V);

return (V)o;

Answer 2

Use int? (ie a nullable int ) instead of int .

Answer 3

int cannot be null as long as it's not an nullable int. If your int can be null it also feels like it's the correct solution to use nullable anyways.