Here's the situation. We're adding a new application to our suite of webapps based on WebForms and so I felt this would be the perfect time to introduce MVC.
I did all the research about intermingling the two and got the project all set up using an Area
that uses MVC routes while the rest of the (visual studio) project runs with web forms the way it's been running.
Master pages were converted to Razor layouts, not too bad because there was only one master page that was shared between every application.
The problem I've run into now is reusing user controls. We have dozens of custom user controls, many of them fairly complex, that are reused throughout all of our applications. Most of them (especially ones that would be difficult to port) do a fair amount with ViewState and postbacks.
If it were just a matter of rewriting these in MVC, the one time cost would be less than ideal but not terrible. But since the existing apps need to be maintained and updated as well, it seems like maintaining 2 versions of the same behaviour using entirely different paradigms would be a huge drain on productivity.
My gut says there isn't really a good solution and we may have to abandon the idea of going to MVC for this project and stick with webforms, but I wanted to see if the SO community has any insight on what to do in this scenario.