One way I have figured out is to store the BackgroundWorkers in a
collection and keep checking their IsBusy property. I am still not sure
if this is the best way to do it. I would really appreciate some help.
So in the code below, I execute a long running operation 10 times; there
is a synchronous version, and then there is an asynchronous version
using BackgroundWorkers? Do you see any problems in using the
BackgroundWorkers this way?
using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.Threading;
using System.Collections;
namespace BackgroundWorkerDemo
{
class Program
{
static void Main(string[] args)
{
DateTime start_time = DateTime.Now;
Console.WriteLine("Program starting");
//RunSyncVersion();
RunAsyncVersion();
DateTime end_time = DateTime.Now;
TimeSpan ts = end_time - start_time;
Console.WriteLine("Program completed. Duration={0}
seconds.", ts.Seconds);
Console.Read();
}
static void worker_RunWorkerCompleted(object sender,
RunWorkerCompletedEventArgs e)
{
}
//Synchronous version
static void RunSyncVersion()
{
for (int i = 0; i <= 10; i++)
{
LongRunningOperation(i);
}
}
//This version uses the async version
static void RunAsyncVersion()
{
ArrayList lstBGWs = new ArrayList();
for (int i = 0; i <= 10; i++)
{
BackgroundWorker worker = new BackgroundWorker();
worker.DoWork += new DoWorkEventHandler(worker_DoWork);
worker.RunWorkerCompleted += new
RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
lstBGWs.Add(worker);
worker.RunWorkerAsync(i);
}
bool all_workers_have_returned = false;
while (all_workers_have_returned == false)
{
all_workers_have_returned = true;
foreach (BackgroundWorker worker in lstBGWs)
{
if (worker.IsBusy == true)
{
all_workers_have_returned = false;
break;
}
}
}
}
static void worker_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
LongRunningOperation(Convert.ToInt32(e.Argument));
}
//Long running operation
private static void LongRunningOperation(int operation_number)
{
Console.WriteLine("Operation# {0} starting on Thread {1}",
operation_number, Thread.CurrentThread.ManagedThreadId);
for (int i=0; i < 1000000000; i++)
{
}
Console.WriteLine("Finished operation# {0} on Thread {1}",
operation_number, Thread.CurrentThread.ManagedThreadId);
}
}
}
-----Original Message-----
From: Discussion of advanced .NET topics.
[mailto:[EMAIL PROTECTED] On Behalf Of Greg Young
Sent: Thursday, July 19, 2007 1:53 PM
To: [email protected]
Subject: Re: [ADVANCED-DOTNET] Question about the right way to use
BackGroundWorker
Why not use ThreadPool.QueueUserWorkItem each with its own event it sets
then use WaitHandle.WaitAll(WaitHandle[] waitHandles) as opposed to
creating a new thread for each?
http://www.codeproject.com/csharp/eventsthreadsync.asp is an example of
events http://msdn2.microsoft.com/en-us/library/27y100eh.aspx is the
overload you probably want to use (supports a timeout) the page also
includes an example (using the threadpool).
Cheers,
Greg Young
On 7/19/07, Peter Ritchie
<[EMAIL PROTECTED]> wrote:
> You can't. The default behaviour of BackgroundWorker is the raise the
> progress and completed events on the thread that created
> BackgroundWorker. If you block the thread until DoSomething returns
> the Completed and Progress event's will never get the thread need to
> raise them. You'd be deadlocked.
>
> On Thu, 19 Jul 2007 10:57:25 -0700, Chopra, Arvinder [Beeline]
> <[EMAIL PROTECTED]> wrote:
>
> >Consider this pseudocode:
> >
> >Public void DoSomething()
> >{
> > Foreach (pending_job job in ListOfPendingJobs)
> > {
> > job.ExecuteLongOperation();
> > }
> >
> > Return to caller;
> >}
> >
> >What I want to do is to execute the job.ExecuteLongOperation() on a
> >separate thread using BackGroundWorker(). The question is what is the
> >best practice/pattern to make sure all BackGroundWorkers have
> >finished execution before the above method returns.
>
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