from How to load / call functions from a VB DLL by Gordon
A brief overview on how to create a DLL in VB .Net which can be used from within Matlab.

VB_Dll_Demo.m
% Example code of how to load a VB DLL and call its function
% See Supporting PDF documentation for more details

clc

vb_dll_demo = actxserver('VB_Dll_Demo.ComClass1');   % DLLName.ClassName

methods(vb_dll_demo)

vb_dll_demo.Adder(10,13)

Contact us at files@mathworks.com