Get actual type of T in a generic List

Question

How do I get the actual type of T in a generic List at run time using reflection?

Answer 1

You can use Type.GetGenericArguments to return the type T in a List.

For example, this will return the Type for any List passed as an argument:

Type GetListType(object list)
{
    Type type = list.GetType();
    if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(List<>))
        return type.GetGenericArguments()[0];
    else
        throw new ArgumentException("list is not a List", "list");
}