TPL wait for task to complete with a specific return value

Question

I\'d like to make a request to X different web services who will each return either true or false.

These tasks should be executed in parall

Answer 1

You can simply use Task.WhenAny and a predicate multiple times until the "right" task comes along

async Task WhenAny(IEnumerable> tasks, Func predicate)
{
    var taskList = tasks.ToList();
    Task completedTask = null;
    do
    {
        completedTask = await Task.WhenAny(taskList);
        taskList.Remove(completedTask);
    } while (!predicate(await completedTask) && taskList.Any());

    return completedTask == null ? default(T) : await completedTask;
}