'System.Threading.Tasks.Task' does not contain a definition for 'Result'

asp.net, asp.net-4.0, asp.net-mvc-3

Solution

The problem is the `Queue<Task>`. `Task` alone does not have a `Result` property. However, `Task<Foo>` has a `Result` property of type `Foo`. (I don't know what `client.Get(...)` returns, let's call it `Foo` for now:

var taskQueue = new Queue<Task<Foo>>();

The `ContinueWhenAll` method does not support `Queue<>`, only `Task[]` and `Task<>[]`, so you need to convert it to an array first.

Task.Factory.ContinueWhenAll(
    taskQueue.ToArray(),
    tasks =>
    {
        var results = tasks.Select(t => t.Result);
        foreach (var result in results)
        {
            ...
        }
    });
}

Problem

I have a facebook query which is as follows ``` var client = new FacebookClient(accessToken); var dynamic = client.Get(connection, new { fields = "name,from,story,message,picture,comments", limit = count}); foreach (var dynPost in results.data) { posts.Add(ConvertToPost(dynPost)); } ``` I am trying to make this quicker by making lots of smaller requests to Facebook in parallel. ``` using (profilingService.Start("Facebook calls")) { var pullSize = 25; var numberOfCalls = (int)Math.Ceiling(count / (double)pullSize); var taskQueue = new Queue<Task>(); for (int i = 0; i < numberOfCalls; i++) { taskQueue.Enqueue(Task.Factory.StartNew(() => { var offset = i * pullSize; var client = new FacebookClient(accessToken); return client.Get(connection, new { fields = "name,from,story,message,picture,comments", limit = 25, offset = offset }); })); } Task.Factory.ContinueWhenAll( taskQueue, tasks => { //t.Result here is giving me the error var results = tasks.Select(t => t.Result); foreach (var result in results) { foreach (var dynPost in result.data) { posts.Add(ConvertToPost(dynPost.data)); } } }); } ``` First of all I am getting an error on `var results = tasks.Select(t => t.Result);` Error 361 'System.Threading.Tasks.Task' does not contain a definition for 'Result' and no extension method 'Result' accepting a first argument of type 'System.Threading.Tasks.Task' could be found (are you missing a using directive or an assembly reference?) t is of type `Task<AntecedentResult>` Which led me to this page, but have still not able to resolve it. What's wrong with this async Task method? Also, I haven't had much experience with this sort of parallel coding, anything I am doing wrong or should be doing in a different way?

Original source

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