Page 119 - CSharp/C#

Chapter 13: Async/await, Backgroundworker,

Task and Thread Examples

Remarks

To run any of these examples just call them like that:

static void Main()
{
new Program().ProcessDataAsync();
Console.ReadLine();
}

Examples

ASP.NET Configure Await

When ASP.NET handles a request, a thread is assigned from the thread pool and a request
context is created. The request context contains information about the current request which can
be accessed through the static HttpContext.Current property. The request context for the request is
then assigned to the thread handling the request.

A given request context may only be active on one thread at a time.

When execution reaches await, the thread handling a request is returned to the thread pool while
the asynchronous method runs and the request context is free for another thread to use.

public async Task<ActionResult> Index()
{
// Execution on the initially assigned thread
var products = await dbContext.Products.ToListAsync();

// Execution resumes on a "random" thread from the pool
// Execution continues using the original request context.
return View(products);
}

When the task completes the thread pool assigns another thread to continue execution of the
request. The request context is then assigned to this thread. This may or may not be the original
thread.

Blocking

When the result of an async method call is waited for synchronously deadlocks can arise. For
example the following code will result in a deadlock when IndexSync() is called:

https://riptutorial.com/ 65