異步控制器行爲

Question

AsyncManager.Parameters["headlines"] = value;被分配的頭條新聞價值。但是，當NewsCompleted方法被調用headlines都變得無效。

public void NewsAsync(string city) 
    { 
     AsyncManager.OutstandingOperations.Increment(); 
     NewsService newsService = new NewsService(); 
     newsService.GetHeadlinesCompleted += (value) => 
     { 
      AsyncManager.Parameters["headlines"] = value; 
      AsyncManager.OutstandingOperations.Decrement(); 
     }; 
     newsService.GetHeadlinesAsync(city); 
    } 

    public ActionResult NewsCompleted(string[] headlines) 
    { 
     return View("News", new ViewStringModel 
     { 
      NewsHeadlines = headlines 
     }); 
    } 

1.）我該如何調試？

2），也當OutstandingOperations數變爲0，框架調用我的actionCompleted方法，由線程池中請求新的線程。當這個actionCompleted方法被調用時，我查看了調用堆棧，並不知道背後究竟發生了什麼。我的意思是框架如何知道應該調用這個特殊的actionCompleted方法與AsyncManager這個參數？

感謝您的幫助。

Answer 1

嘗試這些調整..

public void NewsAsync(string city) 
{ 
    AsyncManager.OutstandingOperations.Increment(); 
    NewsService newsService = new NewsService(); 
    newsService.GetHeadlinesCompleted += (sender, args) => 
    { 
     AsyncManager.Parameters["headlines"] = args.Result; 
     AsyncManager.OutstandingOperations.Decrement(); 
    }; 
    newsService.GetHeadlinesAsync(city); 
} 

public ActionResult NewsCompleted(object headlines) 
{ 
    return View("News", new ViewStringModel 
    { 
     NewsHeadlines = (string[])headlines 
    }); 
}