How to get IObservable<T>.ToTask functionality in silverlight

How can I achiev开发者_高级运维e the behavior you get with IObservable ToTask method in Silverlight where the TPL is not provided ? I want exceptions to get promoted up results as IEnumerable and be able to block and wait for Observable to complete.

Here is an example of what I'm doing with ToTask :

int collectionSize = 200;
service.Collection.CreateSampleCollection(size: collectionSize).Wait();
var query = (QuerySource)service.Collection.CollectionTestModel.All();
var queryTask = query.ToTask();
query.Fetch();
var entities = queryTask.Result;
CollectionAssert.AreEquivalent(entities.Select(e => (int)(long)e["Number"]), Enumerable.Range(0, collectionSize));
service.Collection.DeleteTestCollection().Wait();

So what would be a simple way to translate this code in to other RX extensions ? Using Run I have to add onNext and onError(?) and I have to aggregate the results in onNext. Is there a simpler way to do this ?

You can use First() to block until there is a value available (likewise, Last also blocks).

If you need all the values, you can download the latest build of Rx and use .ToArray().First().

And if you don't have the latest build of Rx, ToList is easy enough to write anyways:

public static List<T> ToList<T>(this IObservable<T> This)
{
    return This.Aggregate(new List<T>(), (acc, x) => {
        acc.Add(x);
        return acc;
    }).First();
}