Waiting for background thread.

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Graham Allwood - 29 Jul 2004 14:22 GMT

Hi,

I have a windows forms application that starts a background thread when it
loads. The background thread is intended to load some data from a database,
this data is required later on in the app (say on some menu option being
chosen). Now, if this menu option is chosen I check the state of the
background thread and if it is still running I want to wait until it
finishes.

Can someone tell is it is ok use the following to pause the UI whilst the
background thread finishes:

myBackgroundThreadAsyncResult.AsyncWaitHandle.WaitOne();

Or is there a better way of waiting for this thread to finish. Perhaps using
Join() from the UI thread?

Any comments?

Regards

Graham

Reply to this Message

Stoitcho Goutsev \(100\) [C# MVP] - 29 Jul 2004 14:52 GMT

Graham,

Either will work, however you will have the same problem of blocked UI
thread - freezed UI. Porbably it doesn't make a lot of sense to use a worker
thread if you going to block the main thread anyways.

You may consider using some kind of notification (event) that the worker
thread may fire when it is done. It would be easely achieved by using
thread-pool threads. To do that create a delegate for the method you want to
execute in a worker thread. Call delegate's BeginInvoke methods and pass
AsyncCallback delegate to a method that will execute when the worker thread
finishes

For more info and example looka at MSDN
- off-line -
ms-help://MS.VSCC.2003/MS.MSDNQTR.2003APR.1033/cpguide/html/cpovrasynchronou
sprogrammingoverview.htm

- or on-line-
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cp
ovrasynchronousprogrammingoverview.asp

More specifically look at the section
'Executing a Callback Method When an Asynchronous Call Completes'

Signature

HTH
Stoitcho Goutsev (100) [C# MVP]

> Hi,
>
[quoted text clipped - 18 lines]
>
> Graham

Reply to this Message

Graham Allwood - 30 Jul 2004 10:13 GMT

Sounds like a good idea. I presume I could then disable the menu option
until the async call had completed.

Thanks.

> Graham,
>
[quoted text clipped - 11 lines]
> For more info and example looka at MSDN
> - off-line -

ms-help://MS.VSCC.2003/MS.MSDNQTR.2003APR.1033/cpguide/html/cpovrasynchronou

> sprogrammingoverview.htm
>
> - or on-line-

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cp
ovrasynchronousprogrammingoverview.asp

> More specifically look at the section
> 'Executing a Callback Method When an Asynchronous Call Completes'
[quoted text clipped - 23 lines]
> >
> > Graham

Reply to this Message

Rate this thread:

Waiting for background thread.

Free Magazines