Loading Static Data from Database in an RIA Application - wcf

Question

As part of a WCF RIA application I'm creating, I'd like to cache a bunch of static supporting data locally (lists of water systems, countries, provinces; that sort of thing.) I've created a simple static class to cache the lists into (LocalStateContainer.cs).
Example:
public static class LocalStateContainer
{
private static IEnumerable _waterSystems;
public static IEnumerable WaterSystems
{
get
{
if (_waterSystems== null)
{
DomainDataSource ds = new DomainDataSource();
Web.SuperDomainContext d = new Web.SuperDomainContext();
ds.DomainContext = d;
ds.QueryName = "GetWaterSystems";
ds.Load();
_waterSystems = ds.Data;
}
return _waterSystems;
}
}
}
Is it prudent to use a DomainDataSource in this way? Could I not just as easily go:
public static class LocalStateContainer
{
private static IEnumerable _waterSystems;
public static IEnumerable WaterSystems
{
get
{
if (_waterSystems== null)
{
Web.SuperDomainContext d = new Web.SuperDomainContext();
_waterSystems = from w in d.WaterSystems select w;
}
return _waterSystems;
}
}
}
More broadly, when is it smart to use a DomainDataSource to retrieve data versus accessing the DomainContext directly? I imagine for 2-way linking the DomainDataSource is the way to go, but is it harmful/foolish to yank static data directly out of the DomainContext?
Any insight is appreciated; I'm still very new to Silverlight so apologies if this is mickey mouse stuff.
Thanks!

Answer 1

I wouldn't bother with a DomainDataSource here, just have a static myDomainContext in App.cs that you can ping:
LoadOperation<my_entity> loadComplete = App.myDAL.Load(App.myDAL.Getmy_entityQuery());
And then if you care about knowing when it's done fetching:
loadComplete.Completed += new EventHandler(loadChain_Completed);
void loadChain_Completed(object sender, EventArgs e)
{
//Stuff to do when data has been fetched, for example
return App.myDAL.my_entitys.ToList();
}