How to call complex return value method in C# dll?

Development Programming & Scripting
1

I need to load a method in C# dll.
this method like this : public List GetAllUser().
right, this method return value is very complex.
I know how to load a method that return simple value like float, string, int.

but List, I can’t.

So, help me please. thanks

my English is very poor, so. excuse me.

2

this method like this : public List《User》 GetAllUser().