MultiThreaded Form

[Ken Saganowski]

Does anyone have any sample code for a multi threaded form that refreshes
itself while an extended operation is executing:

Example: I am updating a local dataset which could potentially have 1000's
of records. I would like to update a label in the meantime but the problem
is that the form seems to be locked while this operation is executing.

Any advice would be greatly appreciated.

[Dmitriy Lapshin [C# / .NET MVP]]

Re: MultiThreaded Form

Look at the "Safe, Simple Multithreading in Windows Forms" series by Chris
Sells in MSDN.

--
Dmitriy Lapshin [C# / .NET MVP]
X-Unity Test Studio

http://www.x-unity.net/teststudio.aspx

Bring the power of unit testing to VS .NET IDE

"Ken Saganowski" <ksaganowski@hi llier.com> wrote in message
news:uoRcG6m6DH A.2404@TK2MSFTN GP11.phx.gbl...[color=blue]
> Does anyone have any sample code for a multi threaded form that refreshes
> itself while an extended operation is executing:
>
> Example: I am updating a local dataset which could potentially have[/color]
1000's[color=blue]
> of records. I would like to update a label in the meantime but the[/color]
problem[color=blue]
> is that the form seems to be locked while this operation is executing.
>
> Any advice would be greatly appreciated.
>
>
>[/color]

[Joe Mayo [C# MVP]]

Re: MultiThreaded Form

"Ken Saganowski" <ksaganowski@hi llier.com> wrote in message
news:uoRcG6m6DH A.2404@TK2MSFTN GP11.phx.gbl...[color=blue]
> Does anyone have any sample code for a multi threaded form that refreshes
> itself while an extended operation is executing:
>
> Example: I am updating a local dataset which could potentially have[/color]
1000's[color=blue]
> of records. I would like to update a label in the meantime but the[/color]
problem[color=blue]
> is that the form seems to be locked while this operation is executing.[/color]

Hi Ken,

You can't make calls back onto your UI thread from a secondary thread with
Windows Forms. Instead, need to use Control.Invoke, or one of a couple
other specialized commands that let you marshal the call back to the main UI
thread. Here's the first in a series of three articles that show you how to
do this and why you are having the problems you see now:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnforms/html/winforms06112002.asp

Joe
--

http://www.csharp-station.com

[Ken Saganowski]

Re: MultiThreaded Form

Thanks for the links. Articles contain needed information.

Ken


"Ken Saganowski" <ksaganowski@hi llier.com> wrote in message
news:uoRcG6m6DH A.2404@TK2MSFTN GP11.phx.gbl...[color=blue]
> Does anyone have any sample code for a multi threaded form that refreshes
> itself while an extended operation is executing:
>
> Example: I am updating a local dataset which could potentially have[/color]
1000's[color=blue]
> of records. I would like to update a label in the meantime but the[/color]
problem[color=blue]
> is that the form seems to be locked while this operation is executing.
>
> Any advice would be greatly appreciated.
>
>
>[/color]

[Ignacio Machin \( .NET/ C# MVP \)]

Re: MultiThreaded Form

Hi Ken,

I just posted some code to do this, see the thread Re: Progress bar without
GUI code in the model? a few post above your.

IF you have any doubt post back.

Cheers,

--
Ignacio Machin,
ignacio.machin AT dot.state.fl.us
Florida Department Of Transportation

"Ken Saganowski" <ksaganowski@hi llier.com> wrote in message
news:uoRcG6m6DH A.2404@TK2MSFTN GP11.phx.gbl...[color=blue]
> Does anyone have any sample code for a multi threaded form that refreshes
> itself while an extended operation is executing:
>
> Example: I am updating a local dataset which could potentially have[/color]
1000's[color=blue]
> of records. I would like to update a label in the meantime but the[/color]
problem[color=blue]
> is that the form seems to be locked while this operation is executing.
>
> Any advice would be greatly appreciated.
>
>
>[/color]

[Bret Pehrson]

Re: MultiThreaded Form

If you don't need interactivity, stay away from multithreading -- it isn't
necessary. Simply add a call to Refresh() after you update the label text:

Label label;
label.Text = "Processing record " + rec_num.ToStrin g();
label.Refresh() ;

If you need interactivity w/ your user interface (e.g. you need to allow the
user to cancel the operation mid-stream), you either have to resort to running
the processing in a background thread (i.e. multithreaded) or occasionally
allow messages to be processed (not multi-threaded):


for (/* main processing loop*/)
{
// do one iteration of work

// process any pending messages
// Note: this uses the Win32 api, convert to .NET
while (PeekMessage(.. ., PM_REMOVE))
{
TranslateMessag e(...);
DispatchMessage (...);
}

// break out if user pressed cancel
if (cancel_operati on)
{
break;
}
}

Dig?


Ken Saganowski wrote:[color=blue]
>
> Does anyone have any sample code for a multi threaded form that refreshes
> itself while an extended operation is executing:
>
> Example: I am updating a local dataset which could potentially have 1000's
> of records. I would like to update a label in the meantime but the problem
> is that the form seems to be locked while this operation is executing.
>
> Any advice would be greatly appreciated.[/color]

--
Bret Pehrson
mailto:bret@inf owest.com
NOSPAM - Include this key in all e-mail correspondence <<38952rglkwdsl >>