First, let’s clear up some terminology: “asynchronous” (async) means that it may yield control back to the calling thread before it starts. In an async method, those “yield” points are await expressions. This is very different than the term “asynchronous”, as (mis)used by the MSDN documentation for years to mean “executes on a background thread”. … Read more
In most project types, your async “up” and “down” will end at an async void event handler or returning a Task to your framework. However, Console apps do not support this. You can either just do a Wait on the returned task: static void Main() { MainAsync().Wait(); // or, if you want to avoid exceptions … Read more
If I execute an asynchronous method and it runs, it surely runs on another thread. No, it typically runs on another thread. It does not surely run on another thread. Stop thinking about threads for a moment and think about the nature of asynchrony. The nature of asynchrony is: I’ve got some workflow that I … Read more
I may be missing something You are. what is the difference between doing Task.Wait and await task? You order your lunch from the waiter at the restaurant. A moment after giving your order, a friend walks in and sits down next to you and starts a conversation. Now you have two choices. You can ignore … Read more
async Task<int> LongTask1() { … return 0; } async Task<int> LongTask2() { … return 1; } … { Task<int> t1 = LongTask1(); Task<int> t2 = LongTask2(); await Task.WhenAll(t1,t2); //now we have t1.Result and t2.Result }
Read up on Cancellation (which was introduced in .NET 4.0 and is largely unchanged since then) and the Task-Based Asynchronous Pattern, which provides guidelines on how to use CancellationToken with async methods. To summarize, you pass a CancellationToken into each method that supports cancellation, and that method must check it periodically. private async Task TryTask() … Read more
After you use WhenAll, you can pull the results out individually with await: var catTask = FeedCat(); var houseTask = SellHouse(); var carTask = BuyCar(); await Task.WhenAll(catTask, houseTask, carTask); var cat = await catTask; var house = await houseTask; var car = await carTask; You can also use Task.Result (since you know by this point … Read more
The ASP.NET Web API has replaced the WCF Web API previously mentioned. I thought I’d post an updated answer since most of these responses are from early 2012, and this thread is one of the top results when doing a Google search for “call restful service C#”. Current guidance from Microsoft is to use the … Read more
This is likely TL;DR for many, but, I think comparing await with BackgroundWorker is like comparing apples and oranges and my thoughts on this follow: BackgroundWorker is meant to model a single task that you’d want to perform in the background, on a thread pool thread. async/await is a syntax for asynchronously awaiting on asynchronous … Read more
my result looks like this: public static async Task<string> Upload(byte[] image) { using (var client = new HttpClient()) { using (var content = new MultipartFormDataContent(“Upload—-” + DateTime.Now.ToString(CultureInfo.InvariantCulture))) { content.Add(new StreamContent(new MemoryStream(image)), “bilddatei”, “upload.jpg”); using ( var message = await client.PostAsync(“http://www.directupload.net/index.php?mode=upload”, content)) { var input = await message.Content.ReadAsStringAsync(); return !string.IsNullOrWhiteSpace(input) ? Regex.Match(input, @”http://\w*\.directupload\.net/images/\d*/\w*\.[a-z]{3}”).Value : null; } … Read more