Does async Page_Load work in asp.net 4.5 dev preview? RSS

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  mdonatas

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  4 Posts

  Does async Page_Load work in asp.net 4.5 dev preview?

  Oct 10, 2011 05:26 PM|LINK

  Hello,

  In Async CTP preview there is sample called: (C# Anders) RSS Aggregator
  And News.aspx.cs has this line:

  protected async void Page_Load(object sender, EventArgs e)

  Or here http://www.asp.net/learn/whitepapers/mvc4-release-notes#_Toc303253813 MVC4 example show how to use async controllers:
  

  public async Task<ActionResult> Index(string city)

  But using VS 11 Dev Preview I didn't have luck using these async features. In webforms in Page_Load setting Literal controls Text property has no effect. Same happens in MVC 4 for Dev Preview 11, when setting ViewBag.Message in async action method, that is not reflected in the output. These scenarious work fine in non-async versions though.

  Does anyone know why?

  • Edited by mdonatas on Oct 10, 2011 05:28 PM
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  xinqiu

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  Re: Does async Page_Load work in asp.net 4.5 dev preview?

  Oct 11, 2011 08:18 PM|LINK

  This sample MVC4 aysnc should work, such as:

      public class HomeController : AsyncController
      {
          [AsyncTimeout(2500)]
          public async Task<ActionResult> Index()
          {
              WebClient wc = new WebClient();

              var result = await wc.DownloadStringTaskAsync("http://aspnet.codeplex.com/project/feeds/rss");

              ViewBag.Message = "test: " + result;

              return View();
          }
         

  For unit test:

         change

           ViewResult result = controller.Index() as ViewResult; 

         to
              ViewResult result = controller.Index().GetAwaiter().GetResult() as ViewResult;

   

   

   

  Thanks and Best Regards
  Xinyang Qiu, Azure Web Platform and Tools team, Microsoft
  • Edited by xinqiu on Oct 11, 2011 11:01 PM
  • Edited by xinqiu on Oct 11, 2011 11:02 PM
  • Edited by mdonatas on Oct 16, 2011 02:11 PM
  • Edited by mdonatas on Oct 16, 2011 02:12 PM
  • Marked as answer by mdonatas on Oct 16, 2011 02:15 PM
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  mdonatas

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  Re: Does async Page_Load work in asp.net 4.5 dev preview?

  Oct 16, 2011 02:15 PM|LINK

  Thanks, that did a thing for MVC, though I still couldn't find what's wrong with WebForms. Any help on WebForms async version of Page_Load is appreciated!

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  levib

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  Re: Does async Page_Load work in asp.net 4.5 dev preview?

  Oct 17, 2011 07:47 AM|LINK

  For WebForms, look at http://forums.asp.net/t/1722876.aspx for an example.  Note: the Page_Load event is itself synchronous, and you call RegisterAsyncTask to tell ASP.NET that it should invoke the asynchronous callback at the appropriate time.  The asynchronous callback you pass to RegisterAsyncTask is invoked immediately after PreRender.