You need to make a small program
Calling a Delphi DLL text from a Vb .NET application
Make the library code yourself, but the goal of the library is to use the input variable text, and the text is returned as well!
//this is the code of the delphi library:
function AddStrings(_a, _b: PWideString ): WideString; export;
Result :=a+' '+b;