Custom Dialog Box

[q1w2e3r4t7]

i want to create a central resource, custom control? or dll? that will provided a list of clients, and return the result to the program.

I have no looked into using custom controls or dll's or yet, however wanted a suggestion as to the most logical direction to head.

I want this resource to be located in the one central location, whereby any improvements / changes i make to 'dialog box' will flow through to all other programs that use it, without having to make changes to each of these programs.

Thanks for any suggestions.