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Error setting Text property inside on thread

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Hello,

I'm trying to use one paralel thread to update some properties from XAML components at runtime, and I don’t want to use the Windows.System.Threading.ThreadPool component instead of System.Threading.Thread. I did some tests using C#, and on the line commented below it throw a catastrophic error “Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))”. See on the piece of code bellow.

        private void TheadStartButton_Click(object sender, RoutedEventArgs e)

        {

            System.Threading.Thread MyThread = new System.Threading.Thread(new System.Threading.ThreadStart(ThreadMethod));

            System.Threading.Thread.Sleep(2000);

            MyThread.Start();

        }

        void ThreadMethod()

        {

            Windows.UI.Popups.MessageDialog BoxOk = new Windows.UI.Popups.MessageDialog("Thread running...");

            BoxOk.ShowAsync().Start();

            //MyTextBlock.Text = "Test...";

        }

Thank you very much for any support.

Monday, January 2, 2012 1:02 PM

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Hi,

It seems a C# code. Any way, you should use the element in the UI thread and call the element's Dispatcher.Invoke/InvokeAsync to set the "MyTextBloc" property.

        void ThreadMethod()
        {
            Windows.UI.Popups.MessageDialog BoxOk = new Windows.UI.Popups.MessageDialog("Thread running...");
            BoxOk.ShowAsync().Start();
            this.Dispatcher.Invoke(Windows.UI.Core.CoreDispatcherPriority.Normal,
                (s,e) => { MyTextBlock.Text = "Test..."; }, this, null);
        }

and below is the C++/CX syntax:

    auto callback = ref new InvokedHandler(
        [this](Object^ sender, InvokedHandlerArgs^ eInvoke) { this->MyTextBlock->Text = "Test..."; },
        CallbackContext::Any
        );
    this->Dispatcher->Invoke(CoreDispatcherPriority::Normal, callback, this, nullptr);

Sincerely,

Bob Bao [MSFT]
MSDN Community Support | Feedback to us

Marked as answer by Leo Soares Tuesday, January 3, 2012 12:58 PM

Tuesday, January 3, 2012 6:17 AM

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Error setting Text property inside on thread

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