Worker threads finish before main thread does??

15 New Member

Hello,

I've written a simple app as a test to run multiple threads from a pool. I'm able to do this, but what's happening is that the main thread finishes before all the workers do. So the Console shows:
"Main thread exits." in between the worker thread strings.

Can anyone see what I'm doing wrong please?

Thanks in Advance!

Here's my code:

Expand|Select|Wrap|Line Numbers

 
using System;

using System.Collections.Generic;

using System.Text;

using System.Threading;

using System.Reflection;
 
namespace ThreadPool2

{

   public static class Example

   {      

      private static int _MaxThreads=2;

      private static ManualResetEvent _DoneEvent;
 
      public static void Main()

      {

         // One event is used for each Method object

         ManualResetEvent[] aDoneEvents = new ManualResetEvent[3];
 
         Type aTestClass = typeof(Tests);
 
         ThreadPool.SetMaxThreads(_MaxThreads, _MaxThreads);
 
         MethodInfo[] aMethods = aTestClass.GetMethods();

         int i = 0;

         foreach(MethodInfo aMethod in aMethods)

            if(aMethod.ReturnType.Name == "Void")

            {               

               aDoneEvents[i] = new ManualResetEvent(false);

               _DoneEvent = aDoneEvents[i];

               ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc), aMethod);
 
               i++;               

            }
 
         WaitHandle.WaitAll(aDoneEvents); //code gets stuck here but I can't see why!
 
         Console.WriteLine("Main thread exits.");

         Console.Read();

      }//Main
 
      // This thread procedure performs the task.

      static void ThreadProc(Object stateInfo)

      {

         object[] aObj = null;
 
         Tests aTests = new Tests(_DoneEvent);
 
         MethodInfo aMethod = stateInfo as MethodInfo;
 
         aMethod.Invoke(aTests, aObj);
 
         aTests.DoneEvent.Set();
 
      }//ThreadProc

   }

}
 
using System;

using System.Collections.Generic;

using System.Text;

using System.Threading;
 
namespace ThreadPool2

{

   public class Tests

   {

      public ManualResetEvent DoneEvent;
 
      public Tests(ManualResetEvent theDoneEvent)

      {

         DoneEvent = theDoneEvent;

      }
 
      public void Test1()

      {

         Console.WriteLine("This is Test 1 Start...");

         Thread.Sleep(2000);

         Console.WriteLine("This is Test 1 Stop...");
 
      }
 
      public void Test2()

      {
 
         Console.WriteLine("This is Test 2 Start...");

         Thread.Sleep(2000);

         Console.WriteLine("This is Test 2 Stop...");
 
       }
 
      public void Test3()

      {
 
         Console.WriteLine("This is Test 3 Start...");

         Thread.Sleep(2000);

         Console.WriteLine("This is Test 3 Stop...");
 
      }
 
   }

}

Oct 11 '07 #1

Subscribe Reply

1708

EricBlair

New Member

I should have realized how sensitive threads are to timing.
Instead of having aglobal DoneEvents, I need to pass it within this loop immediately because by the time I access it beyond here, it wouls have gotten out of synch. So I bundled that data for my callback into a lightweight class that takes the doevents and the method from within the loop and passes it to my worker method.

The gist of the fix is as follows.

class bundleddata
{
MethodInfo Method;
ManualResetEven t MRE;
}

...

MethodInfo[] aMethods = aTestClass.GetM ethods();
int i = 0;
foreach(MethodI nfo aMethod in aMethods)
if(aMethod.Retu rnType.Name == "Void")
{
bundleddata aBD=new bundleddata();
aDoneEvents[i] = new ManualResetEven t(false);
aBD.Method=aMet hod ;
aBD.MRE = aDoneEvents[i];
ThreadPool.Queu eUserWorkItem(n ew WaitCallback(Th readProc), aBD);

i++;
}

Oct 12 '07 #2

Similar topics

3071

Waiting on multiple Threads

by: MikeE | last post by:

Hi all, What's the best way to queue up and wait for number of threads to complete. This problem was trivial in VC++ 6 but I'm finding it rather hard to solve in VB.NET. My calculations run about 2 mins each (on a 2.8 Ghz Xeon and the server range from 2 to 8 processors) (give or take about 15 secs). I have 8 sets of calculations to do (in another app I have 121) all the same calc just different data. But the rest of the processing...

.NET Framework

506

Worker Threads and Events

by: Jacob | last post by:

I'm working on a class that needs to be called from a windows form, do it's work, and then, show progress back to the main form. I'm well aware that worker threads need to call Invoke for updates to the main thread to be threadsafe. I want to make this worker class I'm writing a self contained assembly so that other's can drop it into their projects. My question is: How can I NOT force those implementing my class to have to call...

C# / C Sharp

4999

How to have multiple worker threads submit to one final processing queue? - HELP

by: James Radke | last post by:

Hello, I have a multithreaded windows NT service application (vb.net 2003) that I am working on (my first one), which reads a message queue and creates multiple threads to perform the processing for long running reports. When the processing is complete it uses crystal reports to load a template file, populate it, and then export it to a PDF. It works fine so far....

Visual Basic .NET

2131

Worker thread blocking on calls to .Invoke

by: Jeff Stewart | last post by:

I need a thread to run a subroutine which updates my main form's progress bar. I've properly marshaled all UI updates to the main UI thread, and after the main thread starts the worker thread, it waits for the worker thread to complete by means of a while t.isAlive, sleep(0) mechanism. But when my worker thread calls my UpdateProgressBar routine, which calls Me.Invoke, the invoke call blocks forever. But I can't figure out why the main...

Visual Basic .NET

2695

Technique for Pausing Worker Thread

by: Charles Law | last post by:

My first thought was to call WorkerThread.Suspend but the help cautions against this (for good reason) because the caller has no control over where the thread actually stops, and it might have a lock pending, for example. I want to be able to stop a thread temporarily, and then optionally resume it or stop it for good.

Visual Basic .NET

5995

Communicating between a main thread and a worker thread?

by: Joe Jax | last post by:

I have an object that spawns a worker thread to process one of its methods. That method processes methods on a collection of other objects. During this processing, a user may request to cancel the entire operation. I could request abort on the worker thread, but that is a) potentially messy, and b) not guaranteed to take immediate effect anyway. I would rather have some way of allowing the main thread to tell the worker thread that it...

C# / C Sharp

3548

Best/fastest way to abort worker thread

by: Soren S. Jorgensen | last post by:

Hi, In my app I've got a worker thread (background) doing some calculations based upon user input. A new worker thread might be invoked before the previous worker thread has ended, and I wan't only one worker thread running at any time (if a new worker thread start has been requested, any running worker thread results will be invalid). I'm using the below method to invoke a new worker thread, but when stress testing this I'm sometimes...

C# / C Sharp

7159

What to do while waiting worker threads to finish their job...

by: Ing. Davide Piras | last post by:

Hi there, in my c# .NET 2.0 application I run few threads (from 6 to 12 it depends...) and then my GUI Thread should wait all of them have finished their task... so after create those threads i put them in a List<>, I start them one by one then I do something like: List<ThreadElencoThreadTabelle = new List<Thread>(); ....

C# / C Sharp

1292

Re: Question on threads

by: Steve Holden | last post by:

Jonathan Shao wrote: Yes - you are calling it before you have started ALL your threads, thereby making hte main thread wait for the end of thread 1 before starting the next. An impressive demonstration of thread synchronization, but not quite what you want :-) Try saving the threads in a list then joining them later, like this (untested): threads =

Python

9498

Changing the language in Windows 10

by: Hystou | last post by:

Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...

Windows Server

10364

Problem With Comparison Operator <=> in G++

by: Oralloy | last post by:

Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...

C / C++

10110

The easy way to turn off automatic updates for Windows 10/11

by: Hystou | last post by:

Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...

Windows Server

9967

Discussion: How does Zigbee compare with other wireless protocols in smart home applications?

by: tracyyun | last post by:

Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...

General

6750

Couldn’t get equations in html when convert word .docx file to html file in C#.

by: conductexam | last post by:

I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...

C# / C Sharp

5398

Trying to create a lan-to-lan vpn between two differents networks

by: TSSRALBI | last post by:

Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...

Networking - Hardware / Configuration

5536

Windows Forms - .Net 8.0

by: adsilva | last post by:

A Windows Forms form does not have the event Unload, like VB6. What one acts like?

Visual Basic .NET

3670

How to add payments to a PHP MySQL app.

by: muto222 | last post by:

How can i add a mobile payment intergratation into php mysql website.

PHP

2894

Comprehensive Guide to Website Development in Toronto: Expert Insights from BSMN Consultancy

by: bsmnconsultancy | last post by:

In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

General