Question

Im trying to use the following code:

private Nullable<List<IpAddressRange>> ipAddressRangeToBind;

But I am getting the following warning:

The type List must be a non-nullable value type in
order to use it as a parameter ‘T’ in the generic type or method
‘System.Nullable’.

Answer 1

List<T> is already a reference type (for any kind of T) – you can only declare Nullable<T> where T is a non-nullable value type (it’s declared as Nullable<T> where T : struct).

But that’s okay, because if you just declare:

private List<IpAddressRange> ipAddressRangeToBind;

then you can still have

ipAddressRangeToBind = null;

because reference types are always nullable.