Question

Is it possible to convert a non-nullable value type known only at runtime to nullable? In other words:

public Type GetNullableType(Type t)
{
    if (t.IsValueType)
    {
        return typeof(Nullable<t>);
    }
    else
    {
        throw new ArgumentException();
    }
}

Obviously the return line gives an error. Is there a way to do this? The Type.MakeGenericType method seems promising, but I have no idea how to get a unspecified generic Type object representing Nullable<T>. Any ideas?

Answer 1

you want typeof(Nullable<>).MakeGenericType(t)

Note: Nullable<> without any supplied arguments is the unbound generic type; for more complex examples, you would add commas to suit – i.e. KeyValuePair<,>, Tuple<,,,> etc.