Upgrade CAB and Prism 2 to Prism 4

We have several CAB and prism 2 applications which we plan to migrate to Prism 4.

Has anyone any experiance with migration of CAB and/or Prism 2 applications to Prism 4?

• Are there any "gotchas" that we should be aware off?
• How would you estimate the migration? Would for example x% of original development cost or y hours per screen 开发者_JS百科work.

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I have just upgraded a large (30 module) Prism 2 application. It took about a day in total, but most of that time was spent changing namespaces and references. I followed the information Microsoft supplied when upgrading. Leaving the DI as Unity made the process much easier, it would have probably taken much longer if I had moved from Unity to MEF. I've yet to hit any "gotchas", will update this answer if/when I do.

It's worth noting the changes to commands otherwise you will come across InvalidCastException, T for DelegateCommand is not an object nor Nullable.