ApplicationDeployment.IsFileGroupDownloaded(String) Method

Definition

Namespace:

System.Deployment.Application

Assembly:

System.Deployment.dll

Checks whether the named file group has already been downloaded to the client computer.

public:
 bool IsFileGroupDownloaded(System::String ^ groupName);

public bool IsFileGroupDownloaded (string groupName);

member this.IsFileGroupDownloaded : string -> bool

Public Function IsFileGroupDownloaded (groupName As String) As Boolean

Parameters

groupName

String

The named group of files to download. All files marked "optional" in a ClickOnce application require a group name.

Returns

Boolean

true if the file group has already been downloaded for the current version of this application; otherwise, false. If a new version of the application has been installed, and the new version has not added, removed, or altered files in the file group, IsFileGroupDownloaded(String) returns true.

Exceptions

InvalidDeploymentException

groupName is not a file group defined in the application manifest.

Examples

The following code example downloads all of the files in the HelpFiles group to disk.

void LaunchAppUpdate()
{
    if (ApplicationDeployment::IsNetworkDeployed)
    {
        ApplicationDeployment^ ad =
            ApplicationDeployment::CurrentDeployment;
        ad->UpdateCompleted +=
            gcnew AsyncCompletedEventHandler(this,
            &Form1::LaunchAppUpdate_UpdateCompleted);

        ad->UpdateAsync();
    }
}

void LaunchAppUpdate_UpdateCompleted(Object^ sender,
    AsyncCompletedEventArgs^ e)
{
    if (!e->Cancelled)
    {
        if (nullptr != e->Error)
        {
            System::Windows::Forms::DialogResult dr =
                MessageBox::Show(
                "The application has been updated. Restart?",
                "Restart Application",
                MessageBoxButtons::OKCancel);
            if (System::Windows::Forms::DialogResult::OK == dr)
            {
                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.");
    }
}

private void DownloadFileGroupAsync(string fileGroup)
{
    if (ApplicationDeployment.IsNetworkDeployed)
    {
        ApplicationDeployment deployment = ApplicationDeployment.CurrentDeployment;

        try
        {
            if (!deployment.IsFileGroupDownloaded(fileGroup))
            {
                deployment.DownloadFileGroupProgressChanged += new DeploymentProgressChangedEventHandler(deployment_DownloadFileGroupProgressChanged);
                deployment.DownloadFileGroupCompleted += new DownloadFileGroupCompletedEventHandler(deployment_DownloadFileGroupCompleted);

                deployment.DownloadFileGroupAsync(fileGroup);
            }
        }
        catch (InvalidOperationException ioe)
        {
            MessageBox.Show("This application is not a ClickOnce application. Error: " + ioe.Message);
            return;
        }
    }
}

void deployment_DownloadFileGroupProgressChanged(object sender, DeploymentProgressChangedEventArgs e)
{
    downloadStatus.Text = String.Format("Downloading file group {0}; {1:D}K of {2:D}K completed.", e.Group, e.BytesCompleted / 1024, e.BytesTotal / 1024);               
}

void deployment_DownloadFileGroupCompleted(object sender, DownloadFileGroupCompletedEventArgs e)
{
    if (e.Error != null)
    {
        downloadStatus.Text = "Could not download files. Will try again later.";
        return;
    }
    else if (e.Cancelled)
    {
        downloadStatus.Text = "The file download has been cancelled.";
        return;
    }

    downloadStatus.Text = String.Format("Download of file group {0} complete.", e.Group);
}

Dim WithEvents ADDownloadHelpFiles As ApplicationDeployment

Private Sub DownloadHelpFiles(ByVal GroupName As String)
    If (ApplicationDeployment.IsNetworkDeployed) Then
        ADDownloadHelpFiles = ApplicationDeployment.CurrentDeployment

        If ADDownloadHelpFiles.IsFirstRun Then
            Try
                If Not ADDownloadHelpFiles.IsFileGroupDownloaded(GroupName) Then
                    ADDownloadHelpFiles.DownloadFileGroupAsync(GroupName)
                End If
            Catch ioe As InvalidOperationException
                MessageBox.Show("This application is not a ClickOnce application.")
                Return
            End Try
        End If
    End If
End Sub

Private Sub ADDownloadHelpFiles_DownloadFileGroupProgressChanged(ByVal sender As Object, ByVal e As DeploymentProgressChangedEventArgs) Handles ADDownloadHelpFiles.DownloadFileGroupProgressChanged
    DownloadStatus.Text = String.Format("Downloading file group {0}; {1:D}K of {2:D}K completed.", e.Group, e.BytesCompleted / 1024, e.BytesTotal / 1024)
End Sub

Private Sub ADDownloadHelpFiles_DownloadFileGroupCompleted(ByVal sender As Object, ByVal e As DownloadFileGroupCompletedEventArgs) Handles ADDownloadHelpFiles.DownloadFileGroupCompleted
    DownloadStatus.Text = String.Format("Download of file group {0} complete.", e.Group)
End Sub

Remarks

IsFileGroupDownloaded works in a partially trusted application without any security demands.

When you update an application, ClickOnce copies any on-demand data files from the previous version into the new version's data directory. If you download a new version of these files, you should remove any data you want to keep from the old version and move it into the new version.

See also

• DownloadFileGroup(String)
• DownloadFileGroupAsync