Silverlight

Recently, there’s been a lot of excitement about Silverlight, a rapidly evolving Microsoft technology that
allows a variety of browsers on a variety of operating systems to run true .NET code. Silverlight works
through a browser plug-in, and provides a subset of the .NET Framework class library. This subset
includes a slimmed-down version of WPF, the technology that developers use to craft next-generation
Windows user interfaces.
So where does Silverlight fit into the ASP.NET world? Silverlight is all about client code—quite simply,
it allows you to create richer pages than you could with HTML, DHTML, and JavaScript alone. In many
ways, Silverlight duplicates the features and echoes the goals of Adobe Flash. By using Silverlight in a web
page, you can draw sophisticated 2D graphics, animate a scene, and play video and other media files.
Silverlight is perfect for creating a mini-applet, like a browser-hosted game. It’s also a good choice
for adding interactive media and animation to a website. However, Silverlight obviously isn’t a good
choice for tasks that require server-side code, such as performing a secure checkout in an e-commerce
shop, verifying user input, or interacting with a server-side database. And because Silverlight is still a
new, emerging technology, it’s too early to make assumptions about its rate of adoption. That means it’s
not a good choice to replace basic ingredients in a website with Silverlight content. For example,
although you can use Silverlight to create an animated button, this is a risky strategy. Users without the
Silverlight plug-in won’t be able to see your button or interact with it. (Of course, you could create more
than one front end for your web application, using Silverlight if it’s available or falling back on regular
ASP.NET controls if it’s not. However, this approach requires a significant amount of work.)
In many respects, Silverlight is a complementary technology to ASP.NET. ASP.NET 4 doesn’t
include any features that use Silverlight, but you can freely mix ASP.NET pages and Silverlight pages
on a website—or place Silverlight content in an ASP.NET page. It’s also possible that developers will
some day use ASP.NET web controls that render Silverlight content. Using these controls, you just
might gain the best of both worlds—the server-side programming model of ASP.NET and the rich interactivity of client-side Silverlight.