DownloadProgressChangedEventArgs Class

Definition

Provides data for the DownloadProgressChanged event.

C#
public class DownloadProgressChangedEventArgs : System.ComponentModel.ProgressChangedEventArgs
Inheritance
DownloadProgressChangedEventArgs

Examples

The following code example demonstrates the use of DownloadProgressChangedEventArgs in the context of an application that uses InPlaceHostingManager to download and install a ClickOnce application programmatically.

C#
InPlaceHostingManager iphm = null;

public void InstallApplication(string deployManifestUriStr)
{
    try
    {
        Uri deploymentUri = new Uri(deployManifestUriStr);
        iphm = new InPlaceHostingManager(deploymentUri, false);
    }
    catch (UriFormatException uriEx)
    {
        MessageBox.Show("Cannot install the application: " + 
            "The deployment manifest URL supplied is not a valid URL. " +
            "Error: " + uriEx.Message);
        return;
    }
    catch (PlatformNotSupportedException platformEx)
    {
        MessageBox.Show("Cannot install the application: " + 
            "This program requires Windows XP or higher. " +
            "Error: " + platformEx.Message);
        return;
    }
    catch (ArgumentException argumentEx)
    {
        MessageBox.Show("Cannot install the application: " + 
            "The deployment manifest URL supplied is not a valid URL. " +
            "Error: " + argumentEx.Message);
        return;
    }

    iphm.GetManifestCompleted += new EventHandler<GetManifestCompletedEventArgs>(iphm_GetManifestCompleted);
    iphm.GetManifestAsync();
}

void iphm_GetManifestCompleted(object sender, GetManifestCompletedEventArgs e)
{
    // Check for an error.
    if (e.Error != null)
    {
        // Cancel download and install.
        MessageBox.Show("Could not download manifest. Error: " + e.Error.Message);
        return;
    }

    // bool isFullTrust = CheckForFullTrust(e.ApplicationManifest);

    // Verify this application can be installed.
    try
    {
        // the true parameter allows InPlaceHostingManager
        // to grant the permissions requested in the applicaiton manifest.
        iphm.AssertApplicationRequirements(true) ; 
    }
    catch (Exception ex)
    {
        MessageBox.Show("An error occurred while verifying the application. " +
            "Error: " + ex.Message);
        return;
    }

    // Use the information from GetManifestCompleted() to confirm 
    // that the user wants to proceed.
    string appInfo = "Application Name: " + e.ProductName;
    appInfo += "\nVersion: " + e.Version;
    appInfo += "\nSupport/Help Requests: " + (e.SupportUri != null ?
        e.SupportUri.ToString() : "N/A");
    appInfo += "\n\nConfirmed that this application can run with its requested permissions.";
    // if (isFullTrust)
    // appInfo += "\n\nThis application requires full trust in order to run.";
    appInfo += "\n\nProceed with installation?";

    DialogResult dr = MessageBox.Show(appInfo, "Confirm Application Install",
        MessageBoxButtons.OKCancel, MessageBoxIcon.Question);
    if (dr != System.Windows.Forms.DialogResult.OK)
    {
        return;
    }

    // Download the deployment manifest. 
    iphm.DownloadProgressChanged += new EventHandler<DownloadProgressChangedEventArgs>(iphm_DownloadProgressChanged);
    iphm.DownloadApplicationCompleted += new EventHandler<DownloadApplicationCompletedEventArgs>(iphm_DownloadApplicationCompleted);

    try
    {
        // Usually this shouldn't throw an exception unless AssertApplicationRequirements() failed, 
        // or you did not call that method before calling this one.
        iphm.DownloadApplicationAsync();
    }
    catch (Exception downloadEx)
    {
        MessageBox.Show("Cannot initiate download of application. Error: " +
            downloadEx.Message);
        return;
    }
}

/*
private bool CheckForFullTrust(XmlReader appManifest)
{
    if (appManifest == null)
    {
        throw (new ArgumentNullException("appManifest cannot be null."));
    }

    XAttribute xaUnrestricted =
        XDocument.Load(appManifest)
            .Element("{urn:schemas-microsoft-com:asm.v1}assembly")
            .Element("{urn:schemas-microsoft-com:asm.v2}trustInfo")
            .Element("{urn:schemas-microsoft-com:asm.v2}security")
            .Element("{urn:schemas-microsoft-com:asm.v2}applicationRequestMinimum")
            .Element("{urn:schemas-microsoft-com:asm.v2}PermissionSet")
            .Attribute("Unrestricted"); // Attributes never have a namespace

    if (xaUnrestricted != null)
        if (xaUnrestricted.Value == "true")
            return true;

    return false;
}
*/

void iphm_DownloadApplicationCompleted(object sender, DownloadApplicationCompletedEventArgs e)
{
    // Check for an error.
    if (e.Error != null)
    {
        // Cancel download and install.
        MessageBox.Show("Could not download and install application. Error: " + e.Error.Message);
        return;
    }

    // Inform the user that their application is ready for use. 
    MessageBox.Show("Application installed! You may now run it from the Start menu.");
}

void iphm_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
    // you can show percentage of task completed using e.ProgressPercentage
}

Remarks

In a console application, since events are assigned to threads out of a thread pool, you might receive update progress events out of order, with a subsequent event showing a decrease compared to a previous event. You will not see such behavior in a Windows Forms application, because events in Windows Forms are processed sequentially out of the UI thread's message queue.

Properties

BytesDownloaded

Gets the number of bytes downloaded to the local computer.

State

Gets the progress state of the download.

TotalBytesToDownload

Gets the total number of bytes for the download operation.

Applies to

Prodotto Versioni
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1