C# 4 and .NET 4

1114 ❘ ChaPTer 38 silverliGht
code snippet OutOfBrowserDemo/MainPage.xaml
The constructor MainPage checks whether the application is running out of browser or within the browser
and sets the text of the TextBlock control accordingly. To check if the application is running out of
browser, you can use the IsRunningOutOfBrowser property of the Application class. This class also
provides information about the installation state of the application with the InstallState property.
Possible values are NotInstalled, Installing, Installed, and InstallFailed with the InstallState
enumeration. Using this information, the installButton and updateButton controls are visible
or collapsed.
public MainPage()
{
InitializeComponent();
if (App.Current.IsRunningOutOfBrowser)
{
text1.Text = "running out of browser";
}
else
{
text1.Text = "running in the browser";
updateButton.Visibility = Visibility.Collapsed;
}
if (App.Current.InstallState == InstallState.Installed)
{
installButton.Visibility = Visibility.Collapsed;
}
}
code snippet OutOfBrowserDemo/MainPage.xaml.cs
The event handler OnInstall() is invoked by clicking the associated button. An installation happens just
by invoking the Install() method of the Application class.
private void OnInstall(object sender, RoutedEventArgs e)
{
if (App.Current.InstallState == InstallState.NotInstalled)
{
bool result = App.Current.Install();
if (result)
text1.Text = "installation successful";
}
}
Checking for an update on the server can be done programmatically with the Application class as well.
Here, the update is done in the event handler method OnUpdate(). CheckAndDownloadUpdateAsync()
checks for an available update and installs the update. This is an asynchronous operation using the async
component pattern that fires the event CheckAndDownloadUpdateCompleted on completion of the update.
Success or error information is written in the handler of this event. After a successful update, the new
version is available on the next start.
private void OnUpdate(object sender, RoutedEventArgs e)
{
App.Current.CheckAndDownloadUpdateCompleted += (sender1, e1) =>
{
if (e1.Error != null)
{
text1.Text = e1.Error.Message;
}
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