ApplicationDeployment.CheckForUpdateAsync ApplicationDeployment.CheckForUpdateAsync ApplicationDeployment.CheckForUpdateAsync ApplicationDeployment.CheckForUpdateAsync Method

Definition

Checks UpdateLocation asynchronously to determine whether a new update is available.

public:
 void CheckForUpdateAsync();
public void CheckForUpdateAsync ();
member this.CheckForUpdateAsync : unit -> unit
Public Sub CheckForUpdateAsync ()

Exceptions

ClickOnce throws this exception immediately if you call the CheckForUpdateAsync() method while an update is already in progress.

The deployment manifest cannot be downloaded. This exception appears in the Error property of the CheckForUpdateCompleted event.

The deployment manifest is corrupted. You will likely need to redeploy the application to fix this problem. This exception appears in the Error property of the CheckForUpdateCompleted event.

Examples

The following example checks for an update asynchronously, and installs the update if one exists.

private:
    long sizeOfUpdate;


private:
    void Form1_Load(Object^ sender, System::EventArgs^ e)
    {
        DoUpdate();
    }

public:
    void DoUpdate()
    {
        if (ApplicationDeployment::IsNetworkDeployed)
        {
            ApplicationDeployment^ currentAppDeployment =
                ApplicationDeployment::CurrentDeployment;
            currentAppDeployment->CheckForUpdateCompleted +=
                gcnew CheckForUpdateCompletedEventHandler(
                this, &Form1::currentDeploy_CheckForUpdateCompleted);
            currentAppDeployment->CheckForUpdateAsync();
        }
    }

    // If update is available, fetch it.
    void currentDeploy_CheckForUpdateCompleted(Object^ sender,
        CheckForUpdateCompletedEventArgs^ e)
    {
        if (nullptr != e->Error)
        {
            // Log error.
            return;
        }

        if (e->UpdateAvailable)
        {
            sizeOfUpdate = (long) e->UpdateSizeBytes;
            if (!e->IsUpdateRequired)
            {
                System::Windows::Forms::DialogResult 
                    updateDialogueResult = MessageBox::Show(
                    "An update is available.Would you like to update the" +
                    " application now?", "Update Available",
                    MessageBoxButtons::OKCancel);
                if (System::Windows::Forms::DialogResult::OK == 
                    updateDialogueResult)
                {
                    BeginUpdate();
                }
            }
            else
            {
                BeginUpdate();
            }
        }
    }

    void BeginUpdate()
    {
        ApplicationDeployment^ ad = ApplicationDeployment::CurrentDeployment;
        ad->UpdateCompleted +=
            gcnew AsyncCompletedEventHandler(
            this, &Form1::CurrentDeployment_UpdateCompleted);

        // Indicate progress in the application's status bar.
        ad->UpdateProgressChanged +=
            gcnew DeploymentProgressChangedEventHandler(this, 
            &Form1::ad_ProgressChanged);

        ad->UpdateAsync();
    }

    void CurrentDeployment_UpdateCompleted(Object^ sender,
        AsyncCompletedEventArgs^ e)
    {
        if (!e->Cancelled)
        {
            if (nullptr != e->Error)
            {
                System::Windows::Forms::DialogResult 
                    restartDialogueResult = MessageBox::Show(
                    "The application has been updated. Restart?",
                    "Restart Application",
                    MessageBoxButtons::OKCancel);
                if (System::Windows::Forms::DialogResult::OK == 
                    restartDialogueResult)
                {
                    Application::Restart();
                }
            }
            else
            {
                // Replace with your own error reporting or logging.
                MessageBox::Show(
                    "The application encountered an error in downloading" +
                    " the latest update. Error: {0}",
                    e->Error->Message);
            }
        }
        else
        {
            // Replace with your own error reporting or logging.
            MessageBox::Show("The update of the application's latest" +
                " version was cancelled.");
        }
    }

    void ad_ProgressChanged(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);
        statusStrip1->Text = progressText;
    }
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();
    }
}
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

Remarks

CheckForUpdateAsync returns immediately and starts a separate thread for downloading the updated application. When the method completes or is canceled, it raises the CheckForUpdateCompleted event. You can use AsyncCompletedEventArgs in this event handler to determine whether the operation was canceled, or if an exception was raised during update.

You can cancel an asynchronous update by calling CheckForUpdateAsyncCancel.

Note

If CheckForUpdate discovers that an update is available, and the user chooses not to install it, ClickOnce will prompt the user that an update is available the next time the application is run. There is no way to disable this prompting. (If the application is a required update, ClickOnce will install it without prompting.)

Security

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

Applies to

See also