How to wait all tasks to finished before returning to a view?

Question

I have codes below, but looks like it returns to the view before all of the async tasks have been finished.

How to wait all tasks to finished before returning to a view?

public async Task<IActionResult> Learning01()  
{  
    JObject jo1 = await DoSales_Store1Async(param1);  
    JObject jo2 = await DoSales_Store2Async(param1);  
    JObject jo3 = await DoSales_Store3Async(param1);  
  
    JObject joData = JObject.FromObject(new  
    {  
       jo1 = jo1,  
       jo2 = jo2,  
       jo3 = jo3  
    }  
  
    return await Task.FromResult(Json(joData));  
}  
  
  

Answer 1

@AgaveJoe
yes, you are right!, I missed something there! my bad.
thank you

Answer 2

Also line 14 is just useless code. s/b:

return Json(joData);

Answer 3

It seems to me that async / wait used in your does not make sense. I suggest that you simply write it as follows:

public IActionResult Learning01()  
{  
    // CPU-bound tasks       
      
    return Json(joData);  
}  

The reasons are:

Asynchronous Code Is Not a Silver Bullet
https://learn.microsoft.com/en-us/archive/msdn-magazine/2014/october/async-programming-introduction-to-async-await-on-asp-net#asynchronous-code-is-not-a-silver-bullet

"Async and await on ASP.NET are all about I/O. They really excel at reading and writing files, database records, and REST APIs. However, they’re not good for CPU-bound tasks. You can kick off some background work by awaiting Task.Run, but there’s no point in doing so. In fact, that will actually hurt your scalability by interfering with the ASP.NET thread pool heuristics. If you have CPU-bound work to do on ASP.NET, your best bet is to just execute it directly on the request thread. As a general rule, don’t queue work to the thread pool on ASP.NET."

Avoid blocking calls
https://learn.microsoft.com/en-us/aspnet/core/performance/performance-best-practices?view=aspnetcore-6.0#avoid-blocking-calls

"ASP.NET Core already runs app code on normal Thread Pool threads, so calling Task.Run only results in extra unnecessary Thread Pool scheduling."