Asynchronous Coding in C#

Question

What does await keyword do in C# ? I would love to have explanation in simple words. Lay man's definition would be appreciated.

Jaish Mathews · Answer

I am not covering asynchronous operations as you specifically asked for wait. Understood your confusion on wait, especially you might be thinking why wait if it's Asynchronous? An area which is too granular and depend on specific scenario, explaining in 1-2 words would be difficult So for a layman, picture would tell a lot. See below You have 2 methods and inside 1st method, you have 3 asynchronous operations and 2nd method doing 2 asynchronous operations. Your objective is Asynchronous opeations of Method1 to finish 1st and then only all Asynchronous operations of Method2 to start. These shouldn't be any overlapping acess of threads between them. Now you call Method1 and Method2 from another method, Method3, like below without wait. Method3() { Method1(); Method2() } Here issue is that some of the Method2 Asynchronous operations may start without waiting for Method1 operations to finish as thread is all based on availability. You haven't method level execution control here. So you can ask to wait after Method1 call. This ensures Asynchronous operations still inside Method1(), but any Method2() Asynchronous operations will only start after Method1() finish. So we attains below granular controls over execution flow. 1. Specific Asynchronous operations inside methods still available 2. Method level control to wait among Asynchronous operations for a sequential method call. Hope you got the idea.

Jaish Mathews · Answer

"wait" is on-demand and so you can have Asynchronous operations without a wait, if you are not looking any method execution sequence. Old days it was same way using Thread class. But if you use "async" methods, i.e. public async Task Method. There are multiple scenarios. Some scenarios explianed here, https://stackoverflow.com/questions/19786441/call-async-method-without-await-2/19787716

Chintan Dave · Answer

Thanks Jaish..... Can you suggest any good resource from where I can learn more about ascynchronous methods in C# from scratch ? That will be more helpful to me to get details from one place rather than wandering to many websites

Chintan Dave · Answer

Thanks Jaish...Your explanation is quite conducive for me to understand await in better manner.... From your explanation,it seems that await keyword blocks other asynchronous calls from being executed. Then counter question for this ....can we implement asynchronous method calls with out await keyword or not ?

Jenith Thakkar · Answer

When we are dealing with UI and on button click, we use a long running method like reading a large file or something else which will take a long time, in that case, the entire application must wait to complete the whole task. In other words, if any process is blocked in a synchronous application, the entire application gets blocked and our application stops responding until the whole task completes. Asynchronous programming is very helpful in this condition. By using Asynchronous programming, the Application can continue with the other work that does not depend on the completion of the whole task. I Hope you understand it now

Jignesh Kumar · Answer

Please find below to articles which will clear concept of Async https://www.c-sharpcorner.com/article/async-and-await-in-c-sharp/ https://www.c-sharpcorner.com/UploadFile/e70b61/asynchronous-methods-calls-in-C-Sharp/

Asynchronous Coding in C#

Answers (6)