CODEWITHSUNDEEP
c#wpfmultithreading
Stanislav Kholodov
Stanislav Kholodov

Reputation: 55

WPF Access window created on different UI thread

I created new Window on a different thread because it has heavy UI operations, that was done to keep my main window run smoothly. Everything works perfectly.

But here is the question:
How I can access newly created window?
After calling Dispatcher.Run() I can not manipulate visualisationWindow anymore. I want to keep access to that newly created window object.

Here is how my window created:

    private void CreateVisualisationWindow()
    {
        Thread VisualisationWIndowThread = new Thread(new ThreadStart(ThreadStartingPoint));
        VisualisationWIndowThread.SetApartmentState(ApartmentState.STA);
        VisualisationWIndowThread.IsBackground = true;
        VisualisationWIndowThread.Start();
    }

    private void ThreadStartingPoint()
    {
        Visualisation visualisationWindow = new Visualisation();
        visualisationWindow.Show();
        System.Windows.Threading.Dispatcher.Run();
    }

Also I tried accessing it through System.Windows.Threading.Dispatcher.FromThread(VisualisationWIndowThread) but seems I misunderstand some core things.

Upvotes: 2

Views: 723

Answers (1)

Coops
Coops

Reputation: 301

I simulated your issue using two WPF Window objects and a timer to ensure that the Second Window was created before calling operations on it. Below is my code sample and it updates the second Windows TextBox every five seconds:

    private Timer _timer;
    private SecondWindow _secondWindow;

    public MainWindow()
    {
        InitializeComponent();
        CreateVisualisationWindow();
        _timer = new Timer(Callback);
        _timer.Change(5000, 5000);
    }

    private void Callback(object state)
    {
        UpdateSecondWindowText();
    }

    private void CreateVisualisationWindow()
    {
        Thread VisualisationWIndowThread = new Thread(ThreadStartingPoint);
        VisualisationWIndowThread.SetApartmentState(ApartmentState.STA);
        VisualisationWIndowThread.IsBackground = true;
        VisualisationWIndowThread.Start();
    }

    private void ThreadStartingPoint()
    {
        _secondWindow = new SecondWindow();
        _secondWindow.SecondWindowTextBlock.Text = "Hello";
        _secondWindow.Show();
         Dispatcher.Run();
    }

    private void UpdateSecondWindowText()
    {
        _secondWindow.Dispatcher.BeginInvoke(new Action(() =>
        {
            _secondWindow.SecondWindowTextBlock.Text = _secondWindow.SecondWindowTextBlock.Text + " World";
        }));
    }

So the trick is, you need to call the Dispatcher on the second Window in order to gain access to it.

Upvotes: 2

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