[EricBlair]

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:

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1. using System;
2. using System.Collections.Generic;
3. using System.Text;
4. using System.Threading;
5. using System.Reflection;
6.  
7. namespace ThreadPool2
8. {
9.    public static class Example
10.    {      
11.       private static int _MaxThreads=2;
12.       private static ManualResetEvent _DoneEvent;
13.  
14.       public static void Main()
15.       {
16.          // One event is used for each Method object
17.          ManualResetEvent[] aDoneEvents = new ManualResetEvent[3];
18.  
19.          Type aTestClass = typeof(Tests);
20.  
21.          ThreadPool.SetMaxThreads(_MaxThreads, _MaxThreads);
22.  
23.          MethodInfo[] aMethods = aTestClass.GetMethods();
24.          int i = 0;
25.          foreach(MethodInfo aMethod in aMethods)
26.             if(aMethod.ReturnType.Name == "Void")
27.             {               
28.                aDoneEvents[i] = new ManualResetEvent(false);
29.                _DoneEvent = aDoneEvents[i];
30.                ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc), aMethod);
31.  
32.                i++;               
33.             }
34.  
35.          WaitHandle.WaitAll(aDoneEvents); //code gets stuck here but I can't see why!
36.  
37.          Console.WriteLine("Main thread exits.");
38.          Console.Read();
39.       }//Main
40.  
41.       // This thread procedure performs the task.
42.       static void ThreadProc(Object stateInfo)
43.       {
44.          object[] aObj = null;
45.  
46.          Tests aTests = new Tests(_DoneEvent);
47.  
48.          MethodInfo aMethod = stateInfo as MethodInfo;
49.  
50.          aMethod.Invoke(aTests, aObj);
51.  
52.          aTests.DoneEvent.Set();
53.  
54.       }//ThreadProc
55.    }
56. }
57.  
58.  
59.  
60. using System;
61. using System.Collections.Generic;
62. using System.Text;
63. using System.Threading;
64.  
65. namespace ThreadPool2
66. {
67.    public class Tests
68.    {
69.       public ManualResetEvent DoneEvent;
70.  
71.       public Tests(ManualResetEvent theDoneEvent)
72.       {
73.          DoneEvent = theDoneEvent;
74.       }
75.  
76.  
77.       public void Test1()
78.       {
79.          Console.WriteLine("This is Test 1 Start...");
80.          Thread.Sleep(2000);
81.          Console.WriteLine("This is Test 1 Stop...");
82.  
83.       }
84.  
85.       public void Test2()
86.       {
87.  
88.          Console.WriteLine("This is Test 2 Start...");
89.          Thread.Sleep(2000);
90.          Console.WriteLine("This is Test 2 Stop...");
91.  
92.        }
93.  
94.       public void Test3()
95.       {
96.  
97.          Console.WriteLine("This is Test 3 Start...");
98.          Thread.Sleep(2000);
99.          Console.WriteLine("This is Test 3 Stop...");
100.  
101.       }
102.  
103.    }
104. }
105.  
106.  
107.  
108.  
109.  

[EricBlair]

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;
ManualResetEvent MRE;
}

...

MethodInfo[] aMethods = aTestClass.GetMethods();
int i = 0;
foreach(MethodInfo aMethod in aMethods)
if(aMethod.ReturnType.Name == "Void")
{
bundleddata aBD=new bundleddata();
aDoneEvents[i] = new ManualResetEvent(false);
aBD.Method=aMethod ;
aBD.MRE = aDoneEvents[i];
ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc), aBD);

i++;
}