We know how to obfuscate our Silverlight code, but still it's hard to debug it in browser directly. Silverlight Spy will help us in this.

Silverlight Spy provides detailed runtime inspection of any Silverlight application. Use the built-in browser to navigate to a web page. Silverlight Spy automatically detects the applications embedded in the page and provides various inspection view panes. Explore the XAP package, Isolated Storage, monitor performance, browse the UI visual and logical tree, examine objects, execute code in the DLR shell and more.

Here is Main Window View:

Silverlight Spy comes with various so-called application views that provide access to different parts of a Silverlight application. The following views are available:

• Application Settings
• XAP Package
• UI Automation Styles
• User Interface Explorer
• Object Browser
• DLR Shell

All of them can bee seen at the right bottom of the screen:

It will help to track the performance of your application. It has different tabs for Memory, Process, Processor, Frame Rate and Isolated Storage. Also you can view the content of Isolated Storage. Also export or delete files available in both Application and Site isolated storage.

The monitor provides multiple real-time performance metrics.

Event Monitor is another important tool built inside the Silverlight Spy , basically Event monitor monitors and reports every event which is getting fired ranging from Mouse Enter to GotFocus and all other events , its very helpful when you want to know why your specific event is not firing or what is causing your event to not fire , its really helpful in those situations.

Another good things is that you can customize which events you want to fire leaving other unnoticed because many times you would not like to fire the mouseEnter event every time because its really irritating.

It also comes with a Cross-Domain access Policy Validator.

Silverlight Spy is a ClickOnce WPF application – that means that you don’t have to worry about installation and updates – it installs when you run it, and updates automatically each time you run it. It also supports the .NET Reflector via configuration to supercharge your debugging experience right in the IDE. You just set path to the .NET Reflector directory and it's begin to work.

In addition Application Analyzer will increase the performance.

Application Analyzer consists of two tabs one tab contains the rules and another tab contains the results which are shown after the analyze process is complete.Rules consist of Deployment Rules and Performance Rules.

Very interesting for the programmers will be Dynamic Language Runtime tab.

Use it to execute dynamic language code such as Ruby and Python right in the Silverlight application's AppDomain. The DLR shell is a very powerful tool that allows you to inspect and modify the application in ways that have not been seen before. The shell comes with a set of samples that should get you started.

In total, it's a very useful for developers. But only previous versions of it were free. Now the First Floor Software Company have set a price for 69 euros. If you are the company owner - the price will be 99 euros.

Official website: First Floor Software Company.

There is Labs section where you can find some previous company applications. Slideshow and some page transition navigation. They've build with Silverlight 2.0 , but with sources, so you can investigate them.