InPlaceHostingManager.DownloadApplicationAsync Method

Definition

Namespace:

System.Deployment.Application

Assembly:

System.Deployment.dll

Downloads an application update in the background.

public:
 void DownloadApplicationAsync();

public void DownloadApplicationAsync ();

member this.DownloadApplicationAsync : unit -> unit

Public Sub DownloadApplicationAsync ()

Exceptions

InvalidOperationException

Raised if this method is called before the GetManifestAsync() and AssertApplicationRequirements() methods.

Examples

The following code example demonstrates the use of DownloadApplicationAsync, which it calls at the end of a successful GetManifestCompleted event handler.

The following code examples assume that you have already defined and created an instance of InPlaceHostingManager named iphm.

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;
}
*/

    Private Sub iphm_GetManifestCompleted(ByVal sender As Object, ByVal e As GetManifestCompletedEventArgs) Handles iphm.GetManifestCompleted
        ' Check for an error.
        If (e.Error IsNot Nothing) Then
            ' Cancel download and install.
            MessageBox.Show("Could not download manifest. Error: " & e.Error.Message)
            Return
        End If

        ' Dim isFullTrust As Boolean = CheckForFullTrust(e.ApplicationManifest)

        ' Verify this application can be installed.
        Try
            ' the true parameter allows InPlaceHostingManager
            ' to grant the permissions requested in the application manifest. 
            iphm.AssertApplicationRequirements(True)
        Catch ex As Exception
            MessageBox.Show("An error occurred while verifying the application. " & _
                            "Error text: " & ex.Message)
            Return
        End Try

        ' Use the information from GetManifestCompleted() to confirm 
        ' that the user wants to proceed.
        Dim appInfo As String = "Application Name: " & e.ProductName
        appInfo &= ControlChars.Lf & "Version: " & e.Version.ToString()
        appInfo &= ControlChars.Lf & "Support/Help Requests: "

        If Not (e.SupportUri Is Nothing) Then
            appInfo &= e.SupportUri.ToString()
        Else
            appInfo &= "N/A"
        End If

        appInfo &= ControlChars.Lf & ControlChars.Lf & _
            "Confirmed that this application can run with its requested permissions."

        ' If isFullTrust Then
        '    appInfo &= ControlChars.Lf & ControlChars.Lf & _
        '        "This application requires full trust in order to run."
        ' End If

        appInfo &= ControlChars.Lf & ControlChars.Lf & "Proceed with installation?"

        Dim dr As DialogResult = MessageBox.Show(appInfo, _
            "Confirm Application Install", MessageBoxButtons.OKCancel, MessageBoxIcon.Question)
        If dr <> System.Windows.Forms.DialogResult.OK Then
            Return
        End If

        ' Download the deployment manifest. 
        ' Usually, this shouldn't throw an exception unless 
        ' AssertApplicationRequirements() failed, or you did not call that method
        ' before calling this one.
        Try
            iphm.DownloadApplicationAsync()
        Catch downloadEx As Exception
            MessageBox.Show("Cannot initiate download of application. Error: " & downloadEx.Message)
            Return
        End Try
    End Sub

#If 0 Then
    Private Function CheckForFullTrust(ByVal appManifest As XmlReader) As Boolean
        Dim isFullTrust As Boolean = False

        If (appManifest Is Nothing) Then
            Throw New ArgumentNullException("appManifest cannot be null.")
        End If

        Dim xaUnrestricted As 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 Then
            If xaUnrestricted.Value = "true" Then
                Return True
            End If
        End If

        Return False
    End Function
#End If

Remarks

You must call this method after calling AssertApplicationRequirements.