ApplicationDeployment.CheckForUpdateAsync Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Checks UpdateLocation asynchronously to determine whether a new update is available.
public:
void CheckForUpdateAsync();public void CheckForUpdateAsync ();member this.CheckForUpdateAsync : unit -> unitPublic 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.)