I was having an email conversation with a friend on WPF yesterday and he suggested putting it into a blog post after I went on and on for a bit (sorry Raj!).
Having spent some time learning Silverlight (which is a subset of WPF for the web, Microsoft’s equivalent of Flash) I have really come to like the new programming model in WPF and how easily it allows you to do things that were simply impossible to do in WinForms (ever tried to put a rounded corner to a rectangle anyone?).
To those not familiar with WPF, it’s powered by DirectX so you get hardware acceleration and can use features such as transparency, gradients and transformations. Its programming model enables clear separation of the UI from business logics because you now have to build your UI using a declarative language – XAML (Extensible Application Markup Language).
The event model has also been revamped and it’s now possible to ‘route’ an event so it originates from one element but is raised by another. WPF supports several types of routed events, but Silverlight only allows bubbled events which cascades up the containment hierarchy from deeply nested element to its containers.
Why is Declarative UI better?
Whilst declarative UI is something of a shock to the system to most of us (web developers not included!) it actually makes perfect sense because it helps solve one of the biggest problems in UI development – business logic embedded in UI.
A declarative UI makes it harder to write business logic into the UI because you’re writing less code. However, it’s not about separation of tiers, but separation of concerns, so when you find problems there is a smaller blast radius! Which again, all comes down to loose coupling — the same thing people are trying to achieve with IoC and Dependency Inversion from a dependency point of view.
So all’s well with WPF and industry veterans are all raving about it (there’s a number of shows on DotNetRocks alone which covers WPF and Declarative UI) so why is there still a distinct lack of real-world apps out there? Besides the odd project on CodePlex like Family Show and Scott Hanselman’s BabySmash, I haven’t found too many examples out there (it’s a shame Photology’s dead.. :-( )
I think there are two main reasons why a lot of people are still not adopting WPF, neither has anything to do with the technology itself which is like a fancy new drug which makes you never want to go back! And there are plenty of industry support both in terms of third party support (well known UI controls producers like teleriks, infragistics already offer numerous UI packages for WPF and Silverlight) and backing from the industry veterans.
1. it’s still fairly young
Having only made it into the core .Net platform since .Net 3.0 (nov 2006) it is still fairly new to most developers considering that most people are still happy using .Net 2.0 (I know this is definitely true in the banking/enterprise world!) which equates to:
- a lack of existing expertise in the field, making it hard for would-be adopters because it adds to the cost of adoption in time and expense regardless of their strategy to acquire these expertise, i.e. new recruit vs. training existing staffs
- an additional risk with adopting WPF because you have to first migrate your platform to .Net 3.0, which, should be minimal because it’s really just an add-on to the .Net 2.0 framework. But then again, “why fix what’s not broken?”
2. it’s only a viable option for new developments
Because WPF introduces a completely new set of technologies and a new programming model to boot, it’ll require significant time and effort to convert an existing UI application. This means WPF is only worth considering for new developments.
As with all things Microsoft, there’s a strong focus on enterprise users and I’m sure their representatives would continue to make a push for their partners to adopt WPF and dare I say once they decide to jump on board MS would have a problem stopping them from coming back for more! Yup, WPF is that good!
With the .Net platform going strong as ever (mentioned in 44% of developer jobs posted in the UK in the last 6 months), the universal adoption of WPF as the de facto standard for developing UI application should only be a matter of time. Given the risk-adverse nature of large enterprises (who, given their size and financial muscles, have more say on technology trends than anyone else), it’s no surprise to me that WPF has not really caught on, but as more and more enterprises jump on the WPF bandwagon they’ll in turn increase the size of the talent pool available to others and really set the ball rolling.
Prism: patterns & practices Composite Application Guidance for WPF and Silverlight site