Years ago I got a C# job based on my experience w/ Java which is not that different (plus at that point I'd just gotten off my own Annus Mirabilis where I had gotten an enormous number of broken projects out of the doghouse and/or in front of customers for a failing web agency and demonstrated that I could pick up any kind of tools and get it done.)

Personally I think hiring managers love portfolio projects: people who don't have them are always complaining that they spend 10 years coding Cold Fusion or something but can't talk about or show anything because (1) it is all proprietary and (2) they didn't really understand a lot about it.