Application Class
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Encapsulates a Windows Phone application.
Assembly: System.Windows (in System.Windows.dll)
XMLNS for XAML: Not mapped to an xmlns.
The Application type exposes the following members.
| Name | Description | |
|---|---|---|
 | ApplicationLifetimeObjects | Gets the application extension services that have been registered for this application. |
 | Current | Gets the Application object for the current application. |
| Host | Gets various details about the Windows Phone application's host. |
| Resources | Gets a collection of application-scoped resources, such as styles, templates, and brushes. |
| RootVisual | Gets or sets the main application UI. |
| Name | Description | |
|---|---|---|
 | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
 | Finalize | Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.) |
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetResourceStream(Uri) | Returns a resource file from a location in the application package. |
| GetResourceStream(StreamResourceInfo, Uri) | Returns a resource file from a location in the specified zip package. |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| LoadComponent | Loads a XAML file that is located at the specified Uniform Resource Identifier (URI) and converts it to an instance of the object that is specified by the root element of the XAML file. |
| MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
| Terminate | Terminates the current process. |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
| Name | Description | |
|---|---|---|
 | Exit | Occurs just before an application shuts down and cannot be canceled. |
| Startup | Occurs when an application is started. |
| UnhandledException | Occurs when an exception that is raised by Windows Phone is not handled. |
Application is a class that encapsulates a Windows Phone application and provides the following services:
Application Entry Point
Application Lifetime
Application Management
Application-Scoped Resources
Unhandled Exception Detection
The entry point in a Windows Phone application is the class in your application assembly that derives from Application. This class is known as the application class. When the applicaton starts metadata in the application package is used to instantiate the application class. At this point, the application's lifetime starts. The lifetime of an application occurs in the following order:
Construction (Application)
Application Running
...
User navigates away from the application.
Application reactivated by user.
Application Shutting Down (initiated by user)
Once an application is running, the Application object and its state can be accessed from the static Current property. The singleton pattern ensures that state managed by Application, including shared resources (Resources) and custom properties, is available from a single, application-scoped location.
XAML Usage Notes for the Application class
In practical XAML usage, Application is almost always the root element of the App.xaml file and therefore a practical usage would include the client and XAML xmlns values, as well as an x:Class value for the code-behind that initiates the root visual, as shown in the following XAML fragment.
<Application
x:Class="namespace.class"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone" >
---
</Application>
Technically the XAML usage for any member of the Application class that supports XAML applies both to the Application class and also to any Application subclass that does not specifically disable XAML usage by shadowing members or changing the access level of its constructors. However, the XAML usage for Application members shows the literal Application rather than the placeholder application because subclassing Application is not necessary for most application scenarios, and the XAML usage shows the most common usage patterns whenever possible.
The following code example demonstrates how to use this class to merge the XAML and code-behind portions of a Page class. This code is similar to the InitializeComponent method that Visual Studio generates for the same purpose.
Visual Studio generates the InitializeComponent method when a XAML file has a build action of Page. To load a XAML file using the following example code, set its build action to Resource.