The calling thread must be STA...

[Rainer Queck]

Hi NG,

I am currently exploring VS2008 and WPF.
In a very little WPF-Aplication I am using a System.Timers.T imer and
assigned a Eventhandler to its "Elapsed" event.

When the eventhandler is called, I receive the following error message:
The calling thread must be STA, because many UI components require this.

I assum I need to synchronize the call with the GUI some how.
In Winform applications I used this.InvokeRequ red to detect the neccessary
to do so and the used this.Invoke.

How would I do this with a WPF application now?

Thanks for hints and help.

Regards
Rainer Queck

[Jon Skeet [C# MVP]]

Re: The calling thread must be STA...

On Dec 5, 9:27 am, "Rainer Queck" <Rai...@noemail .noemailwrote:

I am currently exploring VS2008 and WPF.
In a very little WPF-Aplication I am using a System.Timers.T imer and
assigned a Eventhandler to its "Elapsed" event.
>
When the eventhandler is called, I receive the following error message:
The calling thread must be STA, because many UI components require this.
>
I assum I need to synchronize the call with the GUI some how.
In Winform applications I used this.InvokeRequ red to detect the neccessary
to do so and the used this.Invoke.
>
How would I do this with a WPF application now?

See http://msdn.microsoft.com/msdnmag/is...g/default.aspx

Jon

[Roman Wagner]

Re: The calling thread must be STA...

In WPF you should use the Dispatcher Property to start any async
operations.
See the following example the variable _lbl is a label of my form.

public partial class Window1 : System.Windows. Window
{
private Timer _timer = new Timer(1000);

private delegate void DummyDelegate() ;

public Window1()
{
InitializeCompo nent();
_timer.Elapsed += delegate
{
this.Dispatcher .Invoke(
System.Windows. Threading.Dispa tcherPriority.N ormal,
(DummyDelegate)
delegate { _lbl.Content = DateTime.Now.To LongTimeString( ); });
};
_timer.Start();
}

}

[Willy Denoyette [MVP]]

Re: The calling thread must be STA...

"Rainer Queck" <Rainer@noemail .noemailwrote in message
news:edjHLEyNIH A.4712@TK2MSFTN GP04.phx.gbl...

Hi NG,
>
I am currently exploring VS2008 and WPF.
In a very little WPF-Aplication I am using a System.Timers.T imer and
assigned a Eventhandler to its "Elapsed" event.
>
When the eventhandler is called, I receive the following error message:
The calling thread must be STA, because many UI components require this.
>
I assum I need to synchronize the call with the GUI some how.
In Winform applications I used this.InvokeRequ red to detect the neccessary
to do so and the used this.Invoke.
>
How would I do this with a WPF application now?
>
Thanks for hints and help.
>
Regards
Rainer Queck
>

Take a look at the Dispatcher.Invo ke method in System.Windows. Threading.

Willy.

[Rainer Queck]

Re: The calling thread must be STA...

Hi Jon, Willy, Roman,

Thanks for your hints. I have my little app working now.

Regards
Rainer