ApplicationDeployment.UpdateAsync Method ()

 

Starts an asynchronous download and installation of the latest version of this application.

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

Public Sub UpdateAsync

Exception Condition
TrustNotGrantedException

The local computer did not grant this application the permission level it requested to execute.

InvalidDeploymentException

Your ClickOnce deployment is corrupted. For tips on how to diagnose and correct the problem, see Troubleshooting ClickOnce Deployments.

DeploymentDownloadException

The new deployment could not be downloaded from its location on the network.

An application is considered updated when you publish a new version of the application to the location specified by UpdateLocation, and the version number in the application's deployment manifest is greater than the version number of the application currently installed on the user's computer.

While downloading the update, ClickOnce will raise the UpdateProgressChanged event handler on the main application thread to inform you of the status of the download. When the asynchronous update finishes or encounters an exception, ClickOnce will raise the UpdateCompleted event on the main application thread. Examine the AsyncCompletedEventArgs supplied to this event to determine whether the update succeeded.

If UpdateAsync throws an exception, ClickOnce calls UpdateCompleted and sets the Error property of AsyncCompletedEventArgs to the exception that was thrown.

UpdateAsync will download all files in a deployment not marked as "optional" in the application manifest. You can download optional files on demand by using the DownloadFileGroup or the DownloadFileGroupAsync method.

ClickOnce may already be updating the application automatically when you call the UpdateAsync method; if that happens, calls to this method will throw an InvalidOperationException.

If you have updated one or more files in your deployment, but you have not refreshed your application manifest, you will receive an InvalidDeploymentException. Most of the time, rebuilding your application manifest solves this problem. You will also receive this exception if a public-key signature on a deployment manifest or application manifest is invalid or missing.

An update may request a higher level of trust on the local computer than the previous version of the application. If the application uses Trusted Application Deployment, the common language runtime (CLR) trust manager examines the deployment manifest to determine whether it contains a valid trust license. If the deployment manifest does not contain a valid trust license, ClickOnce stops the installation and throws a TrustNotGrantedException. UpdateAsync will never display a prompt asking the user if they want to grant the application permission to run.

The following code example determines whether a new update is available at application load time; if a required update is available, it installs the update asynchronously. The example requires that you deploy a Windows Forms application that includes a StatusStrip control, and that this control contain a ToolStripStatusLabel control named downloadStatus.

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

Private 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


Private 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


Private 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


Private 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

PermissionSet

For full access to the local computer. Associated enumeration: PermissionState.

.NET Framework
Available since 2.0
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