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ApplicationDeployment Class

Updated: July 2008

Supports updates of the current deployment programmatically, and handles on-demand downloading of files. This class cannot be inherited.

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

public sealed 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 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 the CheckForUpdateAsync method; 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 during installation. You can download the files at any point during the application's duration by using the DownloadFileGroup or the DownloadFileGroupAsync method. 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, the 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 class, 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.Application and System.ComponentModel namespaces.

The following code example determines at application load time whether a new update is available; if a required update is available, the code example installs the update asynchronously. This code should be added to a form that contains a TextBox named downloadStatus.

long sizeOfUpdate = 0;

private void UpdateApplication()
{
    if (ApplicationDeployment.IsNetworkDeployed)
    {
        ApplicationDeployment ad = ApplicationDeployment.CurrentDeployment;
        ad.CheckForUpdateCompleted += new CheckForUpdateCompletedEventHandler(ad_CheckForUpdateCompleted);
        ad.CheckForUpdateProgressChanged += new DeploymentProgressChangedEventHandler(ad_CheckForUpdateProgressChanged);

        ad.CheckForUpdateAsync();
    }
}

void  ad_CheckForUpdateProgressChanged(object sender, DeploymentProgressChangedEventArgs e)
{
    downloadStatus.Text = String.Format("Downloading: {0}. {1:D}K of {2:D}K downloaded.", GetProgressString(e.State), e.BytesCompleted/1024, e.BytesTotal/1024);   
}

string GetProgressString(DeploymentProgressState state)
{
    if (state == DeploymentProgressState.DownloadingApplicationFiles)
    {
        return "application files";
    } 
    else if (state == DeploymentProgressState.DownloadingApplicationInformation) 
    {
        return "application manifest";
    } 
    else 
    {
        return "deployment manifest";
    }
}

void ad_CheckForUpdateCompleted(object sender, CheckForUpdateCompletedEventArgs e)
{
    if (e.Error != null)
    {
        MessageBox.Show("ERROR: Could not retrieve new version of the application. Reason: \n" + e.Error.Message + "\nPlease report this error to the system administrator.");
        return;
    }
    else if (e.Cancelled == true)
    {
        MessageBox.Show("The update was cancelled.");
    }

    // Ask the user if they would like to update the application now. 
    if (e.UpdateAvailable)
    {
        sizeOfUpdate = e.UpdateSizeBytes;

        if (!e.IsUpdateRequired)
        {
            DialogResult dr = MessageBox.Show("An update is available. Would you like to update the application now?\n\nEstimated Download Time: ", "Update Available", MessageBoxButtons.OKCancel);
            if (DialogResult.OK == dr)
            {
                BeginUpdate();
            }
        }
        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();
        }
    }
}

private void BeginUpdate()
{
    ApplicationDeployment ad = ApplicationDeployment.CurrentDeployment;
    ad.UpdateCompleted += new AsyncCompletedEventHandler(ad_UpdateCompleted);

    // Indicate progress in the application's status bar.
    ad.UpdateProgressChanged += new DeploymentProgressChangedEventHandler(ad_UpdateProgressChanged);
    ad.UpdateAsync();
}

void ad_UpdateProgressChanged(object sender, DeploymentProgressChangedEventArgs e)
{
    String progressText = 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;
}

void ad_UpdateCompleted(object sender, AsyncCompletedEventArgs e)
{
    if (e.Cancelled)
    {
        MessageBox.Show("The update of the application's latest version was cancelled.");
        return;
    }
    else if (e.Error != null)
    {
        MessageBox.Show("ERROR: Could not install the latest version of the application. Reason: \n" + e.Error.Message + "\nPlease report this error to the system administrator.");
        return;
    }

    DialogResult dr = 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 (DialogResult.OK == dr)
    {
        Application.Restart();
    }
}

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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0

Date

History

Reason

July 2008

Added new members: CheckForDetailedUpdate(Boolean), CheckForUpdate(Boolean)

SP1 feature change.

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