Beatrice Stolnitz discusses the topics UI Virtualization and Data Virtualization in Silverlight 3 and WPF (and the differences in the two implementations) in two interesting articles.

UI Virtualization is the concept that only that part of the UI is rendered which is actually shown. The easiest example is a listbox containing a large amount of items, of which only a handful are shown one screen at the time. Without UI Virtualization, all items would have been rendered, something which might cause performance issues.

Data Virtualization performs this 'culling' even earlier in the databinding process and only binds a small amount of items to the control in the first place. Note that this behaviour does not come out of the box in both WPF and Silverligh 3. Luckily, Beatrice goes out of her way to show us a possible implementation.

I can across the Update Control Library when I read an article in this months Code Magazine by, "INotifyPropertyChanged Is Obsolete" by Michael L Perry.

The library lets you specify 'ordinary' properties which are then treated as Dependency Properties without the need to clutter your code with the INotifyPropertyChanged implementations and firing PropertyChangedEvents yourself. Looks pretty nice, only now you have the problem you need to explicitly mark all non-dependency properties as Independent()...

Last year Stackoverflow.com sort of crahsed into the software development world. I now consider it one of the most likely places of finding a solution for any development question I have. There is only one downside to the website: after I have found what I'm looking for, I ususally spend about an hour simply wandering around reading interesting looking questions totally irrelevant to my original topic :P

WPF, Silverlight, MVC and .NET development in general are well represented at the site, and the master of all questions John Skeet is programming in C#, which oddly enough fills me with pride (some kind of technological chauvinism perhaps?). Nevertheless, the Microsofties live happily together with the Pyhtonese, the Cplusplussers and the Objctive-C-ers. The language agnostic topics tend to be the best! All in all, I love the site.

Then, a couple of weeks ago, Joel announced the Stackoverflow Devdays. I tried to get a ticket through my company, but due to something called recession, they froze all budgets for that kind of thing, so I was on my own. After much deliberation I finally coughed up the €85 (well, I let PayPal cough it up actually) and ordered a ticket! November the 2nd I'll be in Amsterdam! Maybe I'll see you there?

One of the nice additions to Silverlight 3 is the 'out-of-browser' capabilities:

The new out of browser experience in Silverlight 3 enables users to place their favorite Silverlight applications directly onto their PC and Mac, with links on the desktop and start menu—all without the need to download an additional runtime or browser plug-in. Further, the new experience enables Silverlight applications to work whether the computer is connected to the Internet or not—a radical improvement to the traditional Web experience.

Would this eliminate the raison-d'être of the WPF XBAP deployment model? Typically this would be used when you needed a particular functionality that was unavailable in Silverlight but required a sandboxed environment for your application to run in. Now, with the feature set of Silverlight is creeping towards that of WPF and the possibility to run Silverlight out-of-browser, it would seem that XBAP has no role to play anymore.

The functionality offered by Silverlight 3 would simplify the entire distribution and deployment model; simply add a shortcut and the user is always served the latest version of the application.

The only scenario I can think of is running a true 3D application in a browser; obviously it won't take long for someone to create a 3D engine using the SL3 3D projection planes, but true 3D still is beyond the capabilities of Silverlight. Then again, how many people are actually doing this in WPF in the first place?

So, let me know what you think; do XBAPs still have a future?

Charles Petzold has an interesting blogpost on creating the fisheye effect on a row of buttons -similar to that of the OS X dock- both in WPF and in Silverlight. The WPF version was allready explained by him in his Applications = Code + Markup book, which I'm currently re-reading with a vengeance. The Silverlight version can't be completely done in markup.



Petzold is very thorough, which I've come to expect of him and meticulously writes down every improvement he makes to his code and markup. Awesome post.