Sys.Application Class

Provides a run-time object that exposes client events and manages client components that are registered with the application. The members of this object are available globally after the client application has been initialized. The members can be invoked without creating an instance of the class.

Namespace: Sys

Inherits: Sys.Component, Sys.IContainer

Syntax

Sys.Application.addComponent(componentVar);

Members

Name	Description
init Event	Raised after all scripts have been loaded but before objects are created.
load Event	Raised after all scripts have been loaded and after the objects in the application have been created and initialized.
unload Event	Raised before all objects in the client application are disposed.
addComponent Method	Registers a component with the application and initializes it if the component is not already initialized.
dispose Method	Releases resources and dependencies held by the client application.
findComponent Method	Returns the specified Sys.Component object.
getComponents Method	Returns an array of all components that have been registered with the application through the addComponent method.
initialize Method	Initializes the application and raises the load event.
notifyScriptLoaded Method	Called by a referenced script to indicate that the script has been loaded.
queueScriptReference Method	Sequentially queues the scripts to be loaded in the queued order.
raiseLoad Method	Raises the load event.
registerDisposableObject Method	Registers an object that will require disposing with the application.
removeComponent Method	Removes the object from the application and disposes the object if it is disposable.
unregisterDisposableObject Method	Unregisters a disposable object from the application.
isCreatingComponents Property	Gets a value that indicates whether the application is in the process of creating components.

Remarks

The Application object provides functions and events that support client-component development. The Application object is a single instance of the private Sys._Application class. The Application object is created when an ASP.NET AJAX page is viewed in the browser and persists for the life of the page. The Application object is responsible for raising client page life-cycle events such as pageInit, pageLoad, and pageUnload, and for managing the disposal of registered components.

Events

The Application object provides the init, load, and unload events, and it inherits the disposing and propertyChanged events from the base Component class. All of these events apply to the life cycle of the client application in the browser.

If partial-page rendering is supported and the page contains an UpdatePanel control, the PageRequestManager class provides additional events that apply to the parts of the page that are rendered asynchronously. For more information about partial-page rendering, see Partial-Page Rendering Overview.

Individual components can expose events that apply only to the component. They can also access application-level events by using the Application object.

In most cases, page developers should put their code in the load event. At that point in the page life cycle, all scripts are loaded and all components have been created and ready to use. Any code that is included in a function named pageLoad will automatically run when the page loads.

Component developers can access other events or bind additional handlers to the load or unload events by invoking the event's add_ accessor method and passing the handler function. The following example shows how to bind a function named myUnloadHandler to the unload event.

Sys.Application.add_unload(myUnloadHandler)

When an event and its handlers are no longer needed, you can call the remove_ accessor method, as in the following example:

Sys.Application.remove_unload(myUnloadHandler);

You can attach additional handlers to an event by calling the add_ accessor one time for each handler. Handlers are removed individually by calling the remove_ accessor method.

For more information about the Sys.Application events, see ASP.NET AJAX Client Life-Cycle Events.

Adding Components

In most scenarios, you should add components to an application by using the $create command. After a component has been registered with the application, you can access it in the application by calling the findComponent method or the $find shortcut. You can get a list of all available components by calling the getComponents method.

For more information about how to develop components, controls, and behaviors, see ASP.NET AJAX Extensibility.

Referencing Script Files

If you reference a standalone script file (.js file) for use with partial-page rendering, the code in the script file must call the notifyScriptLoaded method. This notifies the application that the script has finished loading. For more information, see notifyScriptLoaded Method.

Documentation for: ASP.NET Ajax Version 1.0