wcfria concurrency clientside - concurrency

Question

I have a bunch of small lookup tables in my database. It would be efficient to load them into local tables before processing the large table. Prefer to do this rather than a complicated join on the server-side and a new metadata type declaration in the middle layer.
So then this code demonstrates my complete lack of any understanding of how concurrency is supposed to work:
protected override void OnNavigatedTo(NavigationEventArgs e)
{
concurrencyFlags = 0;
context.Load<Priorite>(context.GetPrioritiesQuery(), LoadBehavior.RefreshCurrent, prioritiesHaveBeenLoaded, null);
context.Load<Projet>(context.GetProjectsQuery(), LoadBehavior.RefreshCurrent, projectsHaveBeenLoaded, null);
context.Load<TypeTicket>(context.GetTypeTicketsQuery(), LoadBehavior.RefreshCurrent, typeTicketsHaveBeenLoaded, null);
context.Load<Ticket>(context.GetOpenTicketsQuery(), LoadBehavior.RefreshCurrent, ticketsHaveBeenLoaded, null);
while (concurrencyFlags != everythingLoadedNow) System.Threading.Thread.Sleep(1000);
proceedSingleThreadedFromHere();
}
What is the proper way of doing this? Many thanks,

Answer 1

Because you block on the UI thread, the loading may not happen. Also, your UI becomes unresponsive. Instead, you should make the concurrencyFlags a field that can be used when the loads complete.
private int _concurrencyFlags;
protected override void OnNavigatedTo(NavigationEventArgs e)
{
_concurrencyFlags++;
context.Load<Priorite>(context.GetPrioritiesQuery(), LoadBehavior.RefreshCurrent, prioritiesHaveBeenLoaded, null);
_concurrencyFlags++;
context.Load<Projet>(context.GetProjectsQuery(), LoadBehavior.RefreshCurrent, projectsHaveBeenLoaded, null);
_concurrencyFlags++;
context.Load<TypeTicket>(context.GetTypeTicketsQuery(), LoadBehavior.RefreshCurrent, typeTicketsHaveBeenLoaded, null);
_concurrencyFlags++;
context.Load<Ticket>(context.GetOpenTicketsQuery(), LoadBehavior.RefreshCurrent, ticketsHaveBeenLoaded, null);
}
In each method, call proceedSingleThreadedFromHere():
private void prioritiesHaveBeenLoaded(...)
{
// Do work
_concurrencyFlags--;
proceedSingleThreadedFromHere();
}
Check for the value of the _concurrencyFlags before proceeding:
private void proceedSingleThreadedFromHere()
{
if (_concurrencyFlags > 0) return;
// Do work
}
This isn't thread-safe, but WCF RIA calls back on the UI thread by default. So in theory it should be good enough for a prototype.