Remember from the previous sections that an IObservable can be used as a future, a “box” that will eventually contain the result of a web service call or other asynchronous function, or the error information. To this end, we’d really like our web service calls to all be vaguely of the following form:
IObservable<Something> CoolWebServiceCall(object Param1, object Param2 / *etc*/);
Recalling back to previous chapters, we're going to use the Observable.FromAsyncPattern in order to map a Begin/End pair of methods into an Rx async method.
Silverlight's web service generated client code does something a bit annoying—it hides away the BeginXXXX/EndXXXX calls, presumably ...