PB 12.5 Classic how to return a C# dll array

I created a dll in visual studio and using it in PB. I am able to connect to the dll with no problems from PB.

If I call a function on the dll with a return of int or string it works fine but when I need to return an array/structure I get

"error calling external function" How can/do you pass data (rows) back from a dll and into PB?

Thanks

Dave V.