How can I pause a BackgroundWorker? Or something similar

I was using a BackgroundWorker to download some web sites by calling WebClient.DownloadString inside a loop. I wanted the option for the user to cancel in the middle of downloading stuff, so I called CancelAsync whenever I found that CancellationPending was on in the middle of the loop.

But now I noticed that the function DownloadString kinda freezes sometimes, so I decided to use DownloadStringAsync instead (all this inside the other thread created with BackgroundWorker). And since I don't want to rewrite my whole code by having to exit the loop and the function after calling DownloadStringAsync, I made a while loop right after calling it that does nothing but check for a variable bool Stop that I turn true e开发者_开发技巧ither when the DownloadStringCompleted event handler is called or when the user request to cancel the operation.

Now, the weird thing is that it works fine on the debug version; but on the release one, the program freezes in the while loop like if it were the main thread.

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Sounds to me you are busy-waiting with a while loop. You should use event signaling instead, eg. a WaitHandle. A busy-waiting loop in release mode might very well consume all your cpu, giving a feeling of a freeze.

Signal the WaitHandle in DownloadStringCompleted or if the user cancels the download.

Check the MSDN docs on the WaitHandle class. There's also an example there.

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Send your while loop that is checking for the cancelation to sleep for a short while (some ms). This well free up the CPU runtime for other threads and processes.

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nice topic, i used In my background worker process a double while

 int icounter = 1;
 while (icounter < SomeListInventory.Count)
            {
                while (pauseWorker == false)
                { 
                    //-----------------------
                    //DO SOME WORK
                        icounter++;
                    //-----------------------
                }
            }

And i have a button pause, that when i press it, pauseWorker (Global variable or property) becomes true and loops in the first while only, without increasing the icounter, and when i make the pauseworker=false again the process continues