handling app that requires web service - dealing with EndpointNotFoundExceptions - wcf

Question

I'm almost finished my first WP7 application and I'd like to publish it to the marketplace. However, one of the stipulations for a published app is that it must not crash unexpectedly during use.
My application almost completely relies on a WCF Azure Service - so I must be connected to the Internet at all times for my functions to work (communicating with a hosted database) - including login, adding/deleting/editing/searching clients and so forth.
When not connected to the internet, or when the connection drops during use, a call to the web service will cause the application to quit. How can I handle this? I figured the failure to connect to the service would be caught and I could handle the exception, but it doesn't work this way.
LoginCommand = new RelayCommand(() =>
{
ApplicationBarHelper.UpdateBindingOnFocussedControl();
MyTrainerReference.MyTrainerServiceClient service = new MyTrainerReference.MyTrainerServiceClient();
// get list of clients from web service
service.LoginCompleted += new EventHandler<LoginCompletedEventArgs>(service_LoginCompleted);
try
{
service.LoginAsync(Email, Password);
}
**catch (Exception ex)
{
throw new Exception(ex.Message);
}**
service.CloseAsync();
});
EDIT:
My main problem is how to handle the EndpointNotFoundException in WP7 without the application crashing.
Thanks,
Gerard.

Answer 1

Your code should look like
LoginCommand = new RelayCommand(Login);
...
public void Login()
{
var svc = new MyTrainerReference.MyTrainerServiceClient();
try
{
svc.LoginCompleted += LoginCompleted;
svc.LoginAsync();
}
catch (Exception e)
{
svc.CloseAsync();
ShowError(e);
}
}
private void LoginCompleted(object sender, LoginCompletedEventArgs e)
{
((MyTrainerReference.MyTrainerServiceClient)sender).LoginCompleted -= LoginCompleted;
((MyTrainerReference.MyTrainerServiceClient)sender).CloseAsync();
if (e.Error == null && !e.Cancelled)
{
// TODO process e.Result
}
else if (!e.Cancelled)
{
ShowError(e.Error);
}
}
private void ShowError(Exception e)
{
// TODO show error
MessageBox.Show(e.Message, "An error occured", MessageBoxButton.OK);
}
Your code calls LoginAsync and then immediately CloseAsync, I think this will cause problems...