How does task WhenAll work?

How does task WhenAll work?

Task. WhenAll creates a task that will complete when all of the supplied tasks have been completed. It’s pretty straightforward what this method does, it simply receives a list of Tasks and returns a Task when all of the received Tasks completes.

What are task results?

task.Result is accessing the property’s get accessor blocks the calling thread until the asynchronous operation is complete; it is equivalent to calling the Wait method. Once the result of an operation is available, it is stored and is returned immediately on subsequent calls to the Result property.

What does it mean to await a task?

The await operator is applied to a task in an asynchronous method to suspend the execution of the method until the awaited task completes. The task represents ongoing work. That means the await operator blocks the execution of the for loop until it get a responds from the server, making it sequential.

Does task when all run in parallel?

Run will always make a single task per item (since you’re doing this), but the Parallel class batches work so you create fewer tasks than total work items.

Should you use task Result?

Also, using Task. Result inside an async method is a cause for deadlocks and should also be avoided.,Both Result and StartNew are appropriate if you are doing dynamic task parallelism; otherwise, they should be avoided. Neither is appropriate if you are doing asynchronous programming.

Is task Result blocked?

Calling Task. Result should block on any Task/Task. The async CTP just provides an alternative to blocking, by allowing you to await on the task instead of blocking to get the result. If you want to block, you can call Task.

Should I use task WaitAll?

So, if you want to block until all tasks complete then use WaitAll. If you want to just be able to know when all tasks complete but not actually block your code then use WhenAll.

Is task WhenAll thread safe?

From the docs: Public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe. It is safe to perform multiple read operations on a List , but issues can occur if the collection is modified while it’s being read.

What is the point of await async?

Async/await allows to make complicated asynchronous code look as simple as synchronous one.

Does await return a Promise?

Every async function returns a Promise object. Using await will make your function wait and then return a Promise which resolves immediately, but it won’t unwrap the Promise for you. You still need to unwrap the Promise returned by the async function, either using await or using .

How do I get the result of a task?

Once the tasks are completed, you can get the results using.Result or by awaiting them. Task< int > task1 = Task.Run (() => 1); Task< string > task2 = Task.Run (() => “meziantou”); await Task.WhenAll (task1, task2); var task1Result = task1.Result; // or await task1 var task2Result = task2.Result; // or await task2

Should I use await or task result when using whenall?

After you use WhenAll, you can pull the results out individually with await: You can also use Task.Result (since you know by this point they have all completed successfully). However, I recommend using await because it’s clearly correct, while Result can cause problems in other scenarios.

What is the return type of ‘whenall’ in a task?

The return type of WhenAll is a task whose result type is an array of the individual tasks’ result type, in your case Task []> Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. Provide details and share your research!

What is the use of taskwhenall?

At the highest level, Task.WhenAll predates good compiler support for async / await, and was useful when those things didn’t exist. It is also useful when you have an arbitrary array of tasks, rather than 3 discreet tasks. But: we still have the problem that async / await generates a lot of compiler noise for the continuation.