ApplicationDeployment Class

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

Supports updates of the current deployment programmatically, as well as on-demand downloads of files. This class cannot be inherited.

Namespace: System.Deployment.Application
Assembly: System.Deployment (in system.deployment.dll)

'Declaration
Public NotInheritable Class ApplicationDeployment
'Usage
Dim instance As ApplicationDeployment

public final class ApplicationDeployment
public final class ApplicationDeployment

You can configure your ClickOnce application to check for updates and install them automatically through the subscription element of the deployment manifest. Some applications, however, need finer control over their updates. You may want to install required updates programmatically, and prompt users to install optional updates at their convenience. By turning off subscription updates in the deployment manifest, you can take complete control of your application's update policies. Alternatively, you can use the automatic subscription in conjunction with ApplicationDeployment, which enables ClickOnce to update the application periodically, but uses ApplicationDeployment to download critical updates shortly after they are released.

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 on successful completion. 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 complete. 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.

NoteNote

If you update a ClickOnce application while the application is running, your user will not see the updates until you call the Restart method of the Application, which will close the current running instance of the application and immediately restart it.

ApplicationDeployment has no public constructor; you obtain instances of the class within a ClickOnce application through the CurrentDeployment property. You use the IsNetworkDeployed property to verify that the current application is a ClickOnce application.

ApplicationDeployment supports checking for updates and downloading updated files asynchronously by using the new Event-based Asynchronous Pattern Overview, which exposes completion callbacks as class events; ApplicationDeployment starts and manages the threads for you, and calls your application back on the correct UI thread. Through this, you can update without locking up the application, so that the user can continue working while the update installs. If the user must stop all work while an update takes place, consider using the synchronous methods instead.

NoteNote

Performing asynchronous updates requires that your application import both the System.Deployment and System.ComponentModel namespaces.

The following code example determines at application-load time whether a new update is available; if it is a required update, it installs it asynchronously.

Private sizeOfUpdate As Long = 0

Dim WithEvents ADUpdateAsync As ApplicationDeployment

Private Sub UpdateApplication()
    If (ApplicationDeployment.IsNetworkDeployed) Then
        ADUpdateAsync = ApplicationDeployment.CurrentDeployment

        ADUpdateAsync.CheckForUpdateAsync()
    End If
End Sub

Sub ADUpdateAsync_CheckForUpdateProgressChanged(ByVal sender As Object, ByVal e As DeploymentProgressChangedEventArgs) Handles ADUpdateAsync.CheckForUpdateProgressChanged
    DownloadStatus.Text = [String].Format("{0:D}K of {1:D}K downloaded.", e.BytesCompleted / 1024, e.BytesTotal / 1024)
End Sub


Sub ADUpdateAsync_CheckForUpdateCompleted(ByVal sender As Object, ByVal e As CheckForUpdateCompletedEventArgs) Handles ADUpdateAsync.CheckForUpdateCompleted
    If (e.Error IsNot Nothing) Then
        MessageBox.Show(("ERROR: Could not retrieve new version of the application. Reason: " + ControlChars.Lf + e.Error.Message + ControlChars.Lf + "Please report this error to the system administrator."))
        Return
    Else
        If (e.Cancelled = True) Then
            MessageBox.Show("The update was cancelled.")
        End If
    End If

    ' Ask the user if they would like to update the application now.
    If (e.UpdateAvailable) Then
        sizeOfUpdate = e.UpdateSizeBytes

        If (Not e.IsUpdateRequired) Then
            Dim dr As DialogResult = MessageBox.Show("An update is available. Would you like to update the application now?", "Update Available", MessageBoxButtons.OKCancel)
            If (System.Windows.Forms.DialogResult.OK = dr) Then
                BeginUpdate()
            End If
        Else
            MessageBox.Show("A mandatory update is available for your application. We will install the update now, after which we will save all of your in-progress data and restart your application.")
            BeginUpdate()
        End If
    End If
End Sub

Private Sub BeginUpdate()
    ADUpdateAsync = ApplicationDeployment.CurrentDeployment
    ADUpdateAsync.UpdateAsync()
End Sub


Sub ADUpdateAsync_UpdateProgressChanged(ByVal sender As Object, ByVal e As DeploymentProgressChangedEventArgs) Handles ADUpdateAsync.UpdateProgressChanged
    Dim progressText As String = String.Format("{0:D}K out of {1:D}K downloaded - {2:D}% complete", e.BytesCompleted / 1024, e.BytesTotal / 1024, e.ProgressPercentage)
    DownloadStatus.Text = progressText
End Sub


Sub ADUpdateAsync_UpdateCompleted(ByVal sender As Object, ByVal e As AsyncCompletedEventArgs) Handles ADUpdateAsync.UpdateCompleted
    If (e.Cancelled) Then
        MessageBox.Show("The update of the application's latest version was cancelled.")
        Exit Sub
    Else
        If (e.Error IsNot Nothing) Then
            MessageBox.Show("ERROR: Could not install the latest version of the application. Reason: " + ControlChars.Lf + e.Error.Message + ControlChars.Lf + "Please report this error to the system administrator.")
            Exit Sub
        End If
    End If

    Dim dr As DialogResult = MessageBox.Show("The application has been updated. Restart? (If you do not restart now, the new version will not take effect until after you quit and launch the application again.)", "Restart Application", MessageBoxButtons.OKCancel)
    If (dr = System.Windows.Forms.DialogResult.OK) Then
        Application.Restart()
    End If
End Sub

System.Object
  System.Deployment.Application.ApplicationDeployment

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

Community Additions

ADD
Show: