Should I use WPF for business applications?

The conventional wisdom -- and Microsoft guidance -- on "should I use Windows Forms or Windows Presentation Foundation for my business application" is to use Windows Forms.  The justification is that WPF's novel features aren't sufficiently useful to line-of-business applications to balance out Windows Forms' better tools, control set and third-party support.  WPF, it is implied, is only worth the candle if you're doing something amazingly fancy in the way of visual design: a "cool" app rather than a useful one.

I think this is nonsense.

It's certainly true that Windows Forms has the advantages people cite.  But WPF has a number of features which should make it a serious option for anybody developing a new application, no matter how rudimentary the user interface.  Skipping over nice tactical time-savers like layout managers and major but specialised features like navigation and styling, the big two of these are data binding and the rich content model, and particularly the way they work together.

A typical forms application is very data-centric.  While Windows Forms 2.0 delivers substantial improvements to data binding over Visual Basic and WinForms 1.x, it's still relatively limited compared to WPF.  Bidirectional value converters, multibindings, validations and the ability to bind non-primitive types are just a few of the features that make it easier to build data-centric forms in WPF than in Windows Forms, even if those forms are visually quite simple.

But in WPF there's no need for forms to be bald and textual.  The rich content model makes it almost as easy to create simple visualisations as to display raw text.  Sure, if you want elegant or complex visuals, you have some work to do, but in WPF you pay only for what you use: you don't incur the responsibility of having to draw everything from scratch just because you want one of the words on a button to be bold or list box items to be colour coded, or of having to implement all sorts of list control behaviour just because you want to display a collection in a format other than a stack.

This gets really powerful when you start harnessing data binding and the rich content model together.  In Windows Forms, if you want to implement a complex visual interface such as a Gantt chart or a geographical display, you have to write a lot of code to draw the control, handle input such as keyboard and mouse input and manage the view data model (e.g. selection tracking).  A WPF Gantt chart is just a list box with the items rendered as rectangles whose width is bound to duration and whose position is bound to their start time.  Very easy to write, and things like selection management, arrow-key support and mouse selection come for free.  (You have to do a bit more work to allow users to drag the rectangles, but once you've done that, hooking those UI events back to the underlying model is just a matter of making your data bindings two way.)

For me, the killer application of WPF is not bouncing buttons with dancing elves trapped inside them.  The killer application is information visualisation, the kind of things you get from Tufte and the periodic table.  And that's something that even forms-style, line-of-business applications will find worthwhile.