Waiting for Appdomain code to finish

Question

Hi,

I'm creating an Appdomain to run a piece of code that can literally be any thing. I want my host process to be able when all the word is complete but async calls/threads are blocking my efforts. My code is something like this:

AppDomain ad = AppDomain.CreateDomain(...);
WorkUnit mbro = (WorkUnit)ad.CreateInstanceAndUnwrap(...);

mbro.Run();

And work unit does an async call like this:

class WorkUnit {

public override void Run()
{
    WebClient wb = new WebClient();
    wb.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wb_DownloadStringCompleted);
    wb.DownloadStringAsync(new Uri("http://localhost/WhoTouches/ThreadSleep.aspx"));
}

void wb_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
{
    Console.WriteLine("job is done now");
}
}

What I'm looking for is for a way to know when everything is done. I'm not sure how but I found the other day that if you used that WorkUnit inside a ASPX page it wouldn't finish the request until the async webclient call is complete. Point being, its possible but I dunno how.

Answer 1

I'm not familiar with the WorkUnit class, but if you find the thread in which it runs you could use Thread.Join. I'm not sure this answers your question... but perhaps gives you a pointer in the right direction.

Answer 2

if I'm understanding your question correctly you want the main thread to block until async call would finish. In this case I would recommend to use an event object and signal it at the DownloadStringCompleted method of your WorkUnit class. Here's your code slightly modified:

public class WorkUnit : MarshalByRefObject
{
   private AutoResetEvent _event = new AutoResetEvent(false);

   public void Run()
   {
     WebClient wb = new WebClient();
     wb.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wb_DownloadStringCompleted);
     wb.DownloadStringAsync(new Uri("some uri"));

     Console.WriteLine("Waiting for download to comlete...");
     _event.WaitOne();
     Console.WriteLine("done");
   }

   void wb_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
   {
     Console.WriteLine("job is done now");
     _event.Set();
   }
 }

hope this will give you an idea on how to proceed with your task