We have rewritten a WinForms app A as a web app. The old WinForms app had integration with WinForms app B, in that you could fire it up from app A with a set of variables.
Users are now demanding the same functionality from a rewritten web app. My first thought was for WinForms app B to create my own URL protocol (foo://...), but it seems that to do that you have to create keys in HKEY_CLASSES_ROOT - which is an activity done by an admin user. However, the users are basically limited users and WinForms app B is actually a ClickOnce app.
What are my options?
Since App A is now in the cloud and the user interacts with it via the browser, it is sandboxed and many of the things that a desktop app can do are not available to it anymore.
This is a security feature and outside of writing a browser plugin that will bridge between App a on the browser and App b, there isn't much you can do.