Sync with async
- 1. Sync with Async M Prabath Maduranga Peiris MSP / MSA RUSL
- 2. Why Async ? Async allows programmer to avoid performance bottlenecks and improve applications responsiveness. Scenario : Applications access the HTTP (Web ) inside the program Access the web is slow and delayed Total application will be wait Sync With Async - PrabathSL
- 3. Sync With Async - PrabathSL private void uploadImageCallbackHell() { bool BufferStatus = true; var filePicker = new FilePicker(); var PickerTask = filePicker.PickImage(); PickerTask.ContinueWith((PickerReturn) => { if (PickerTask.IsCanceled) { BufferStatus = false; } else { var Uploadtask = new Task<bool>(() => { return sendUpdate(PickerReturn); }); Uploadtask.ContinueWith((UploadReturnTask)()=> { BufferStatus = false; }); } } ); }
- 4. With Async Application can continue with other works that doesn’t depend on blocked resource until the blocked task finished. Sync With Async - PrabathSL
- 5. Async Async programming available with Visual Studio 2012 and .NET framework 4.5 onwards Runtime components support Async: Web ( HttpClient / SyndicationClient ) File Access ( StorageFile / StreamWriter / XmlReader ) Images ( MediaCapture / BitMapEncoder and Decoder ) Sync With Async - PrabathSL
- 6. Concepts in Async Sync With Async - PrabathSL
- 7. Tasks Reasoning about Background operations Task and Task<T> Encapsulate units of works State : Running , Finished , Cancelled Result Thrown Exceptions Sync With Async - PrabathSL
- 8. Working With Tasks Useful Operations Wait : Task.WaitAny(t1,t2,t3) Wait : Task.WaitAll(t1,t1,t3) Chain : task1.ContinueWith(task2) Wrap : Task.WhenAny(t1,t2,t3) Wrap : Task.WhenAll(t1,t2,t3) Sync With Async - PrabathSL
- 9. Async Support Base Class Libraries (BCL) All standard Async API’s from .NET BCL Coverage is .NET 4.5 Complete for BCL What is available on Async Any API that take more than 50ms to run Sync With Async - PrabathSL
- 10. Compiler is Amazing async key word informs the compiler that this method need to be handle with it self await indicates a suspension point where callback need to be generated Continuations are generated after each suspension point Exception handling with Try Catch Remember async and await , then use Tasks Sync With Async - PrabathSL
- 11. How to use Async ? private async void ButtonDefinition() { Async modifier can be on , Methods Lambdas Anonymous methods button.Click += async (sender, e) =>{ int number = await getNumberAsync(); Use Coding standards Use Async Suffix | e.g. DownloadAsync Return Task or Task<T> according to situation void for only event handlers Sync With Async - PrabathSL }; Task<int> itemNumberTask = getNumberAsync(); int num = await itemNumberTask; } private async Task<int> getNumberAsync() { await Task.Delay(200); return 10; }
- 12. Demo Sync With Async - PrabathSL
- 13. Async Execution 1 2 3 private void independentWork() Sync With Async - PrabathSL
- 14. Advanced Tips Working with interdependent Async Operations ?? Mutual exclusion Shared flag Sleep and Wakeup Mutex Semaphore Sync With Async - PrabathSL
- 15. Advanced Tips Task manages set of class Task.WhenAll(Ienumerable<Task>) Require all class to complete Task.WhenAny(Ienumerable<Task>) Require any one of task completed private async Task BulkTaskOperationAsync() Sync With Async - PrabathSL { var t1 = await Task.Factory.StartNew(() => getNumberAsync()); var t2 = await Task.Factory.StartNew(() => getNumberAsync()); Task.WaitAny(t1, t2); }
- 16. Questions Sync With Async - PrabathSL
- 17. Thank You Blog : prabathsl.blogspot.com Email : prabathsl@outlook.com Fb/ Twitter : @mpmpeiris Sync With Async - PrabathSL
Editor's Notes
- #3: Desire to build responsive applications With long running tasks Use background thread Need to have own handshake protocol to calling its done or not , ended up with everyone make their own notification sytems Database access or file access Network connection interference Working with call backs (node js ) pass message to other end of the day it will become more difficult to program
- #6: Support .NET base class libraries . It means what you did with regular .NET and now Async is there
- #8: Task is something like this , It will contains all other properties except the result. State , exceptions etc. All the errors that thrown win the task execution is thrown after await is done.
- #9: Say to wait until any one of these are finished Task 2 starts just after task1 (once file download you can convert it into another format) Task encapsulates those tasks and any of them are finished main task is finished (getting same data from multiple distributed Db’s )
- #10: You ca use sync or async. Decide that make application better
- #11: When await keyword hit compiler going to look at task that is waiting generate code to run that in thread and managed that and error handing
- #12: With Task<int> method its not gonna just ended the task and finish the job. You can read the Task.result property to get int result. But Tasktast<int> itself make query the integer type result in Task.result It returning int, but signature is Task<int>. Compiler identifies the return value is int an in the execution flow it is I task and return it as Task.result at the await finished Await cant use in Catch or finally