How to do the processing and keep GUI refreshed using databinding?

Question

History of the problem

This is continuation of my previous question

How to start a thread to keep GUI refreshed?

but since Jon shed new light on th

Answer 1

In my WPF applications I don't send the property change directly from the model to the GUI. It always goes via a proxy (ViewModel).

The property change events are put in a queue which is read from the GUI thread on a timer.

Don't understand how that can be so much more work. You just need another listener for your model's propertychange event.

Create a ViewModel class with a "Model" property which is your current datacontext. Change the databindings to "Model.Property" and add some code to hook up the events.

It looks something like this:

public MyModel Model { get; private set; }

public MyViewModel() {
    Model = new MyModel();
    Model.PropertyChanged += (s,e) => SomethingChangedInModel(e.PropertyName);
}

private HashSet _propertyChanges = new HashSet();

public void SomethingChangedInModel(string propertyName) {
    lock (_propertyChanges) {
        if (_propertyChanges.Count == 0)
            _timer.Start();
        _propertyChanges.Add(propertyName ?? "");
    }
}

// this is connected to the DispatherTimer
private void TimerCallback(object sender, EventArgs e) {
    List changes = null;
    lock (_propertyChanges) {
        _Timer.Stop(); // doing this in callback is safe and disables timer
        if (!_propertyChanges.Contain(""))
            changes = new List(_propertyChanges);
        _propertyChanges.Clear();
    }
    if (changes == null)
        OnPropertyChange(null);
    else
        foreach (string property in changes)
            OnPropertyChanged(property);
}