Question

public class MyList : List<MyClass>

How can I get the type MyClass through reflection if I have an object that contains an instance of MyList? The list can be empty, so I can’t do something like myList[0].GetType().

p.s. I can’t just stop using MyList and directly use the generic List instead (the situation is a bit more complicated, and there are reasons for “hiding” the generic argument), so I can’t pick up MyClass through GetGenericArguments().

Answer 1

var elementType = (
    from iface in myList.GetType().GetInterfaces()
    where iface.IsGenericType
    where iface.GetGenericTypeDefinition() == typeof(IList<>)
    select iface.GetGenericArguments()[0])
        .Single();

I use IList<T> instead of list. This is more generic. However, there is also the change of a type implementing multiple ILis<T> versions (such as IList<string> and IList<int>).