C# 4 and .NET 4

networking ❘ 1107
}
{
EventList.Add(ev);
}
}
};
client.GetEventsAsync(DateTime.Today, DateTime.Today.AddMonths(2));
The method OnRegistration() is invoked when the Click event of the Submit Registration button is fi red.
Here again, an asynchronous method is invoked: RegisterAttendeeAsync() to register the attendee.
On completion of this method, NavigationService.Navigate() is used to navigate the user to a
different page.
private void OnRegistration(object sender, RoutedEventArgs e)
{
var client = new RegistrationServiceClient();
CurrentAttendee.EventId = (comboEvents.SelectedItem as Event).Id;
client.RegisterAttendeeCompleted += (sender1, e1) = >
{
if (e1.Error == null)
{
if (e1.Result)
{
NavigationService.Navigate(
new Uri("/Success", UriKind.Relative));
}
else
{
NavigationService.Navigate(
new Uri("/ErrorPage", UriKind.Relative));
}
}
else
{
// display error
}
};
client.RegisterAttendeeAsync(CurrentAttendee);
}
Now the Silverlight application can be started to invoke the WCF Web service.
using WCf data services
Silverlight also gives you access to the client part of WCF Data Services. With this, you can use HTTP
requests to retrieve and update data from the Silverlight control without the need to manually defi ne service
methods. Retrieving, updating, and adding new data can be done with simple HTTP requests.
WCF Data Services is covered in Chapter 32, “Data Services.”
To offer a service using WCF Data Services for the Silverlight application, a new WCF Data Service item
named EventRegistrationDataService is added to the Web project. The implementation derives from
DataService < EventRegistrationEntities > . The generic parameter for the base class DataService < T >
is the entity data context that was created by the template for the ADO.NET Entity Framework. With
config.SetEntitySetAccessRule() , access rules are defi ned to allow read and all access to the Events
entity set and the Attendees entity set.
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