Windows Phone 7 and Silverlight Support, A Word of Caution

So, I was at Scott Guthrie’s keynote address at MIX10 yesterday and I walked away scratching my head. On the one hand all the announcements around Windows Phone 7 and its development platform we’re great. I was really glad to see that the tooling falls in line with Microsoft’s history of providing great, integrated tools for developers. I was also happy to see Microsoft breaking away from it’s usual routine and really, I mean, really focus on the user experience. Did they get the UX right? I don’t know. There are bits and pieces I find interesting and other pieces I simply wonder “What were they thinking”, but that’s an entirely different post. The lack of of true “Enterprisey” features other than support for Exchange and Office, also concerns me, but I’m sure those will come in time and with demand. Of course, there’s also the fact that apps don’t really run in the background. However, all of these things aren’t why I was scratching my head yesterday. I was wondering about the elephant in the room. I was wondering why nobody asked the obvisous question. If Windows Phone 7 uses Silverlight as a platform for building native app, will existing “Silverlight-enabled” websites work in the phone’s browser? It seems like such a simple question, one with an obvious answer. But the fact that none of yesterday’s presenters explicitly called it out had me concerned. After all I have some Silverlight apps running around on the interwebs and it would sure be nice if they just worked on Windows Phone 7. People have ripped on that fruit company in Cupertino for a long time for not supporting plug-ins (i.e. Flash or Silverlight) within their mobile broswer, so you think Microsoft would be ready to 1-up them by supporting their own technology (i.e. Silverlight) in the mobile browser of their shiny new device.

Since I didn’t get an answer, I thought I would download the developer bits and give a Silverlight enabled website a go in the WP7 emulator. What better site to use than Silverlight.net. Here’s how the site looks in the desktop version of IE8

Notice the area surrounded by red? This is a Silverlight component. Keep this in mind as you now look at the site in the emulator for WP7:

See that area in red? That’s where the Silverlight component should be! When I saw this I stepped away from desk thinking that this simply couldn’t be. So I created a Silverlight 4 RC app on my machine and tried to browse to it via the emulator. Same result. Still refusing to believe this, and thinking maybe it was just an emulator issue, I hunted down a Microsoft DPE last night to get confirmation. Unfortunately he confirmed my fears. Windows Phone 7 does not support Silverlight within the browser. Let me say that again so you can hear it:

WINDOWS PHONE 7 DOES NOT SUPPORT SILVERLIGHT IN THE BROWSER

I was very confused, and, quite honestly, viscerally angry about this. It seemed like such a no brainer, and I think it’s an initial assumption a lot, A LOT, of people are going to make. After all, there are a ton of Silverlight apps already deployed on the interwebs, and a number of people are going to assume that they’ll just work in the browser on WP7. After all, wouldn’t be in Microsoft’s best interest to say “You know all those existing Silverlight apps you have, they’ll work too!” I’m also suprised at the lack of support of Silverlight in the WP7 browser for another reason. One of the other things we’ve heard at MIX10 is that there’s not an intial way to distribute your apps outside of the app store/marketplace/whatever. This has raised the ire of a number of corporate developers. Allowing the WP7 browser to support Silverlight would seem to solve this problem. However, it would allow people to bypass the app store for deploying their apps, thus reducing a revenue stream for Microsoft. I’m not saying or event suggesting this is the reason WP7 does not support Silverlight in the browser. I’m sure there are techincal reasons, such as the IE browser on WP7 not supporting plug-ins.

With all of this said, you can reuse code across browser hosted and phone hosted applications. I’ll have an upcoming post on that shortly.

All in all, I think the WP7 platform has a lot of promise and potential, and I’m looking forward to working with it. I hope you are too!