ASP.NET Threading Issue

Question

Problem: I am working on a ASP.NET 2.0/C# Application and I need to do the following:

I have a function I am using from a third-party library lets say

MyFunctions.CalculateTotal(int a, int b);

A known issue is that the thread locks resources. So there is another function that needs to be called afterwards to clean everything up.

MyFunctions.ThreadExit();

The issue is that this will exit the current thread and I will not be able to use any other function afterwards. Also, it does not seem appropriate for me to kill an asp.net thread like this.

I have considered spinning a separate thread, but that would be a hack.

Global.asax has those application wide events like Application_Start/End

I know there is no event such as Application_ThreadStart/End, but maybe something like that?

Any other suggestion for a possible solution?

Answer 1

I'm not sure that using a separate thread would be such a hack. It sounds like that is what required.

BTW - that third party library sounds absolutely horrible! ;-)

Answer 2

(Updated)

It sounds like that library wants to make a mess in the current thread and force you to exit the thread if you want it to clean up after itself. In that case, I would always run that method in a separate thread. Untested code:

int result;
var thread = new Thread(_ => {
  result = MyFunctions.CalculateTotal(a, b);
  MyFunctions.ThreadExit();
}).Start();

Answer 3

This article might help you, it involves using an IHttpAsyncHandler - you would then use this as "asynchandler.ashx". It does require you to know a bit about HttpHandlers if you don't already though, so it's not an instant solution.

A slightly modified version of their code with your MyFunctions is:

public class AsyncHandler : IHttpAsyncHandler
{ 
  public void ProcessRequest(HttpContext ctx)
  {
    // not used
  }

  public bool IsReusable
  {
    get { return false;}
  }

  public IAsyncResult BeginProcessRequest(HttpContext ctx, 
                                          AsyncCallback cb, 
                                          object obj)
  {
    AsyncRequestState reqState = 
                      new AsyncRequestState(ctx, cb, obj);
    AsyncRequest ar = new AsyncRequest(reqState);
    ThreadStart ts = new ThreadStart(ar.ProcessRequest);
    Thread t = new Thread(ts);
    t.Start();

    return reqState;
  }

  public void EndProcessRequest(IAsyncResult ar)
  {
    AsyncRequestState ars = ar as AsyncRequestState;
    if (ars != null)
    {
     // here you could perform some cleanup, write something else to the
     // Response, or whatever else you need to do
    }
  }
}

public class AsyncRequest
{
  private AsyncRequestState _asyncRequestState;

  public AsyncRequest(AsyncRequestState ars)
  {
    _asyncRequestState = ars;
  }

  public void ProcessRequest()
  {
    MyFunctions.CalculateTotal(int a, int b);

    // tell asp.net I am finished processing this request
    _asyncRequestState.CompleteRequest();
  }
}

Change their variable names are they're nasty.