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    <p>On the other thread, (in the method you are "queueing" up, add a try catch clause... .Then in the catch, place the caught exception into a shared Exception variable (visible to the main thread).</p> <p>Then in your main thread, when all queued items have finished (use a wait handle array for this) Check if some thread populated that shared exception with an exception... If it did, rethrow it or handle it as appropriate... </p> <p>here's some sample code from a recent project I used this for...<br> HasException is shared boolean... </p> <pre><code> private void CompleteAndQueuePayLoads( IEnumerable&lt;UsagePayload&gt; payLoads, string processId) { List&lt;WaitHandle&gt; waitHndls = new List&lt;WaitHandle&gt;(); int defaultMaxwrkrThreads, defaultmaxIOThreads; ThreadPool.GetMaxThreads(out defaultMaxwrkrThreads, out defaultmaxIOThreads); ThreadPool.SetMaxThreads( MDMImportConfig.MAXCONCURRENTIEEUSAGEREQUESTS, defaultmaxIOThreads); int qryNo = 0; foreach (UsagePayload uPL in payLoads) { ManualResetEvent txEvnt = new ManualResetEvent(false); UsagePayload uPL1 = uPL; int qryNo1 = ++qryNo; ThreadPool.QueueUserWorkItem( delegate { try { Thread.CurrentThread.Name = processId + "." + qryNo1; if (!HasException &amp;&amp; !uPL1.IsComplete) IEEDAL.GetPayloadReadings(uPL1, processId, qryNo1); if (!HasException) UsageCache.PersistPayload(uPL1); if (!HasException) SavePayLoadToProcessQueueFolder( uPL1, processId, qryNo1); } catch (MeterUsageImportException iX) { log.Write(log.Level.Error, "Delegate failed " iX.Message, iX); lock (locker) { HasException = true; X = iX; foreach (ManualResetEvent txEvt in waitHndls) txEvt.Set(); } } finally { lock(locker) txEvnt.Set(); } }); waitHndls.Add(txEvnt); } util.WaitAll(waitHndls.ToArray()); ThreadPool.SetMaxThreads(defaultMaxwrkrThreads, defaultmaxIOThreads); lock (locker) if (X != null) throw X; } </code></pre>
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    1. POHow to catch exceptions from a ThreadPool.QueueUserWorkItem?
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    1. USCharles Bretana
    1. USCharles Bretana
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    1. COwhat is a "shared Exception variable (visible to the main thread)"? What if multiple exceptions are thrown?
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      1. USMedicineMan
    2. COIn sample code above, X is the shared Exception variable... Its just a variable declared at class level so it is "shared" among all methods in class... And As soon as the first exception is thrown, don't you kinda want to stop "?
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      1. USCharles Bretana
 

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