Background worker

[csharpula csharp]

Hello,
Can you please tell me if I should use the background worker in the
following way:
if (worker.IsBusy)
worker.CancelAs ync(); (or I can avoid this if)?

And in case I want to restart the background worker ,should I do it this
way?
worker.RunWorke rAsync();

Thank u !






*** Sent via Developersdex http://www.developersdex.com ***

[Marc Gravell]

Re: Background worker

Regards the "if(worker.IsBu sy)", I imagine that yes, you can drop the
if and just call CancelAsync. I say this because if you *had* to test
IsBusy, you'd already have a race-condition (since the other thread
could complete between the IsBusy and CancelAsync calls). However,
including this test doesn't do much harm.

Regards restarting, that sounds about right - but in this case you
*do* want to check that it isn't already running since it throws an
exception if you try to use it twice at once. There is no race
condition here since it can only become "safer" (if you see what I
mean).

Mar

[=?Utf-8?B?UGV0ZXIgUml0Y2hpZSBbQyMgTVZQXQ==?=]

RE: Background worker

You can "restart" the background worker by calling RunWorkerAsync, but you
won't be able to call that until after you receive the RunWorkerComple ted
event. Until you get that event you'll get an InvalidOperatio nException.

--
Browse http://connect.microsoft.com/VisualStudio/feedback/ and vote.

http://www.peterRitchie.com/blog/

Microsoft MVP, Visual Developer - Visual C#


"csharpula csharp" wrote:

Hello,
Can you please tell me if I should use the background worker in the
following way:
if (worker.IsBusy)
worker.CancelAs ync(); (or I can avoid this if)?
>
And in case I want to restart the background worker ,should I do it this
way?
worker.RunWorke rAsync();
>
Thank u !
>
>
>
>
>
>
*** Sent via Developersdex http://www.developersdex.com ***
>

[Creativ]

Re: Background worker

A question:

ThreadPool also provides the async execution of tasks. So when should
I use ThreadPool and when BackgroundWorke r? What's the difference
between them?

[Peter Duniho]

Re: Background worker

On Mon, 24 Dec 2007 00:42:33 -0800, Creativ <GongXinrong@gm ail.comwrote:

A question:
>
ThreadPool also provides the async execution of tasks. So when should
I use ThreadPool and when BackgroundWorke r? What's the difference
between them?

BackgroundWorke r uses the ThreadPool. It adds to that the ability to deal
with cross-thread issues, by providing an event-driven model for using
it. In particular, the notification events like ProgressChanged and
RunWorkerComple ted will be raised on the same thread that created the
BackgroundWorke r instance. This means you can use the BackgroundWorke r
class from a Form instance, creating it on the main GUI thread for the
Form and not having to worry about using Invoke() or BeginInvoke() to call
code that accesses the Form instance itself.

If your background thread code needs to communicate with a GUI object like
a Form- or Control-derived class, then the BackgroundWorke r class provides
a nice simplified API to do that.

Pete