Is class or struct

Question

How do I check is the type class or struct?

 protected   T GetNullValue<T>(IDataReader reader, int ordinalId)
    {
        if (reader.IsDBNull(ordinalId))
        {
            //if T is struct.....
            //else if I is class
        }
        return (T)reader.GetValue(ordinalId);
    }

Answer 1

if (default(T) is ValueType)
   ...

is the most efficient thing I can come up with at the moment.