Microsoft Silverlight is an open-source development tool that is used for creating and deploying interactive user experiences, internet applications and media experiences for web and mobile application.

The tool used with the Silverlight application is the Microsoft Visual Studio. The applications are written in .NET language. So, all the associated tools with the .NET language will also work with the Silverlight as well. Microsoft Expression Blend is the tool that is used to develop and design the Silverlight user interface applications. Visual studio is the platform that is used to debug the Silverlight errors and use error free applications. Silverlight usually come in the zip format and it contains the .XAP format that consists of one or more .NET managed assemblies that are stored in .DLL files. It also consists of AppManifest.XAML that contains the entry point including the important classes and assemblies.

Event routing is an important concept that is based on the visual tree. Routing of the events support RoutingStragegy of Bubble, Tunnel and Direct methods that are used to make it possible.

• Bubble: is the most used routing method used. It allows a bubble to propagate the visual tree from source element till it is handled differently to reach the root element. It also allows the event of an object to be handled by the element hierarchy coming from the source element.
  
  
• Tunnel: they start at the root element and then traverse down the element in the tree till they have handled and reached the source element of the event. They have their own names that are prefixed with Preview like PreviewMouseDown.
• Direct: are the normal events that handles the event delegates hooked up to an event.

The different classes that are used in Visual tree are as follows:

• ScrollViewer: allows to include an area that is scrollable and contains the visible elements of it like scroll bar.
• ScrollContentPresenter: allows the content of the ScrollViewer to be displayed.
• ItemsPresenter: allows the control of the specific item to be used in a visual tree where it present the items that has to be arranged in a panel using ItemsPanel and ItemsControl.
• VirtualizingStackPanel: this arranges the stack panel and virtualizes the content used in it in a single line that can be made oriented in any direction either horizontal or vertical.
• ContentPresenter: allows the user to present and displays the content of a ContentControl method. It also allows the flow of the content to be managed together in one way and can be represented together.

Silverlight is a plugin that is provided by the Microsoft. Silverlight architecture includes the functionality from core .NET framework, Ajax and having some of its own functionality such as animation, media etc. The architecture consists of four blocks:

• .NET framework components: WPF is .NET framework, used in Silverlight.
• Presentation core: core presentation framework includes the display options such as images, vector animations etc.
• Other technologies: Ajax and JavaScript technologies are used to interact with Silverlight framework.
• Hosting: Silver-light animations run under the browser environment and it also provides lots of other application hosting programs.

Silverlight is a plug-in, which can be used to develop web based or mobile based applications. Silverlight is used in those applications where you need to represent the graphics or the output should be in graphical format. Silverlight can be used in various types of Line-of-Business applications such as: Healthcare, Insurance, Logistics etc. One of the good example of its application is healthcare application.

Moonlight is an Open Source implementation of Silverlight, primarily for Linux and other Unix/X11 based Operating Systems. In September of 2007, Microsoft and Novell announced a technical collaboration that includes access to Microsoft’s test suites for Silverlight and the distribution of a Media Pack for Linux users that will contain licensed media codecs for video and audio.

• The Silverlight plug-in is a very lightweight component that is necessary for users to access Silverlight applications. The plug-in download and install takes only a few moments, and do not take up much hard drive space.
• The Silverlight plug-in is responsible for accessing the Silverlight object in the Web page, downloading and accessing the XAP package, setting up the program environment, and beginning execution of the application.
• When a Web page containing a Silverlight application is displayed, the user should be given a link to download the plug-in from Microsoft if the plug-in is not already installed.

Silverlight SDK is a set of tools, documentation, samples, and templates for web developers to enable them to easily develop Silverlight enabled applications. The SDK is not really mandatory to develop Silverlight applications; however, the SDK will make development much easier.

To change the default page of a Silverlight application, you need to set the RootVisual property inside the Application_Startup event of the App.xaml file. Collapse private void Application_Startup(object sender, StartupEventArgs e) { this.RootVisual = new MainPage(); }

• App.xaml is a file used by Silverlight applications to declare shared resources like brushes, various style objects, templates etc. Also, the code-behind file of app.xaml.cs is used to handle global application level events like Application_Startup, Application_Exit, and Application_UnhandledException (similar to the Global.asax file for ASP.NET applications).
• When Visual Studio creates the app.xaml file automatically, it creates a few event handlers with some default code. You can change the code appropriately. Collapse private void Application_Startup(object sender, StartupEventArgs e) { } private void Application_Exit(object sender, EventArgs e) { } private void Application_UnhandledException(object sender, ApplicationUnhandledExceptionEventArgs e) { } For ASP.NET developers, the above code will look familiar. This is similar to the application level event handlers in Global.asax.