Note: This namespace is new in the .NET Framework version 2.0.

With the System.Deployment.Application namespace, you can program custom upgrade behavior into your ClickOnce application.

The key class in this namespace is ApplicationDeployment. You can test whether your deployment has an available update by using either the CheckForUpdate or CheckForUpdateAsync methods; the latter method raises the CheckForUpdateCompleted event when it has successfully completed. CheckForDetailedUpdate returns important information about the update, such as its version number and whether it is a required update for current users. If an update is available, you can install it by using Update or UpdateAsync; the latter method raises the UpdateCompleted event after installation of the update is finished. For large updates, you can receive progress notifications through the CheckForUpdateProgressChanged and UpdateProgressChanged events, and use the information in ProgressChangedEventArgs to notify the user of the download status.

You can also use ApplicationDeployment to download large files and assemblies on demand. These files must be marked as "optional" within the deployment's application manifest, so that they are not downloaded at installation. You can download the files at any point during the application's duration by using the DownloadFileGroup or DownloadFileGroupAsync methods. You can download assemblies before they are loaded into memory by supplying an event handler for the AssemblyResolve event on the AppDomain class. For more information, see Walkthrough: Downloading Assemblies On Demand with the ClickOnce Deployment API Using the Designer.

 Classes

	Class	Description
	ApplicationDeployment	Supports updates of the current deployment programmatically, as well as on-demand downloads of files. This class cannot be inherited.
	CheckForUpdateCompletedEventArgs	Represents detailed update information obtained through a call to CheckForUpdateAsync.
	DependentPlatformMissingException	Indicates that the platform dependency was not found during activation of the ClickOnce deployment, and that the deployment will not run.
	DeploymentDownloadException	Indicates that there was an error downloading either the ClickOnce manifests or the deployment's files to the client computer.
	DeploymentException	Defines a base class for all deployment-related exceptions.
	DeploymentProgressChangedEventArgs	Represents progress data reported in an asynchronous operation.
	DeploymentServiceCom	Provides internal services for the ClickOnce deployment API.
	DownloadApplicationCompletedEventArgs	Provides data for the DownloadApplicationCompleted event.
	DownloadFileGroupCompletedEventArgs	Describes a file download that has recently completed.
	DownloadProgressChangedEventArgs	Provides data for the DownloadProgressChanged event.
	GetManifestCompletedEventArgs	Provides data for the GetManifestCompleted event.
	InPlaceHostingManager	Manages a ClickOnce deployment.
	InvalidDeploymentException	Indicates that ClickOnce could not read either the deployment or application manifests.
	TrustNotGrantedException	Indicates that the application does not have the appropriate level of trust to run on the local computer.
	UpdateCheckInfo	Represents detailed update information obtained through a call to CheckForDetailedUpdate.

 Delegates

	Delegate	Description
	CheckForUpdateCompletedEventHandler	Represents the method that will handle the CheckForUpdateCompleted event of an ApplicationDeployment.
	DeploymentProgressChangedEventHandler	Represents the method that will handle the CheckForUpdateProgressChanged event, UpdateProgressChanged event, or DownloadFileGroupProgressChanged event of an ApplicationDeployment.
	DownloadFileGroupCompletedEventHandler	Represents the method that will handle the DownloadFileGroupCompleted event of an ApplicationDeployment.

 Enumerations

	Enumeration	Description
	DeploymentProgressState	Specifies the current stage of a ClickOnce download operation.