c#-5.0

I am trying to write a multi threading search and then display all the results once the tasks have finished running but currently I don't understand how to process the results once all the tasks are complete My code is as follows: private async void DoSearchAsync() { var productResults = await SearchProductsAsync(CoreCache.AllProducts); var brochureResults = await SearchBrochuresAsync(CoreCache.AllBrochures); _searchResults.AddRange(productResults); _searchResults.AddRange(brochureResults); ResultsCount = _searchResults.Count; } Where _searchResults is a List<SearchResult> My understanding is

I am trying get my hands dirty with async CTP and I noticed that the compiler complains about the async return type. What is the problem with other types? A simple demo static void Main(string[] args) { DoWork(); Console.WriteLine("Returned to main"); Console.Read(); } // why do I need to return void, Task or Task<T> here? // I know I can use something like Task<IEnumerable<string>> private static async string[] DoWork() { Console.WriteLine("DoWork started"); return await Task.Factory.StartNew( delegate { Thread.Sleep(2000); Console.WriteLine("DoWork done"); return new List<string>(); }); }

Background I have some code that performs batch HTML page processing using content from one specific host. It tries to make a large number (~400) of simultaneous HTTP requests using HttpClient . I believe that the maximum number of simultaneous connections is restricted by ServicePointManager.DefaultConnectionLimit , so I'm not applying my own concurrency restrictions. After sending all of the requests asynchronously to HttpClient using Task.WhenAll , the entire batch operation can be cancelled using CancellationTokenSource and CancellationToken . The progress of the operation is viewable via

I've got a caching class that uses cold (unstarted) tasks to avoid running the expensive thing multiple times. public class AsyncConcurrentDictionary<TKey, TValue> : System.Collections.Concurrent.ConcurrentDictionary<TKey, Task<TValue>> { internal Task<TValue> GetOrAddAsync(TKey key, Task<TValue> newTask) { var cachedTask = base.GetOrAdd(key, newTask); if (cachedTask == newTask && cachedTask.Status == TaskStatus.Created) // We won! our task is now the cached task, so run it cachedTask.Start(); return cachedTask; } } This works great right up until your task is actually implemented using C#5's