Question

I have a chart control in XAML, and datapoints that are bind to the control.
The problem is when my ModelView changes the Collection of points the Chart control doesn’t get any notifications. I have tried dp, with ObservableCollection and INotifyPropertyChanged without any luck. I know that there is a difference between changing a field/property and making collection operations such as (add/remove/replace etc.) for the changes to propagate to the Chart control. But I haven’t got it to work. The change event is only triggered when I instance/reinstance the collection.

Does any have link to a working MVVM that works with collections?

Worth too know.

public class ObservableCollection : Collection, INotifyCollectionChanged, INotifyPropertyChanged

        public static DependencyProperty WorkModelsProperty = DependencyProperty.Register("WorkModels", typeof(ObservableCollection), typeof(Chart),
            new PropertyMetadata(new ObservableCollection { }, new PropertyChangedCallback(
            (sender, args) =>
            {
                Debugger.Break(); //trigged only when collection got new instance
            })));

        public ObservableCollection WorkModels
        {
            get { return (ObservableCollection)GetValue(WorkModelsProperty); }
            set { SetValue(WorkModelsProperty, value); }
        }

The binding is correct and tested.
Code in Window.Resources.

ObjectDataProvider ObjectType="{x:Type vm:ListWorkViewModel}" x:Key="ListWorkViewModel"

The binding of control.

WorkModels="{Binding Source={StaticResource ListWorkViewModel}, Path=WorkModels}"

In the ViewModel I use the following code to rise changes. (When using INotifyPropertyChanged)

WorkModels.Add(workModel);
this.RaisePropertyChanged("WorkModels");

protected void RaisePropertyChanged(string propertyName)
{
     VerifyPropertyName(propertyName);
     if (PropertyChanged != null)
          PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}

When I use ObservableCollection I only add new data point to the collection.

WorkModels.Add(workModel);

Question on MVVM pattern on WPF?

Answer 1

Thank you for answers. I found the solution to the problem here.
http://msdn.microsoft.com/en-us/library/aa970563.aspx

For a dependency property in general, the implementation pattern that you follow is that you define a CLR property wrapper, where that property is backed by a DependencyProperty identifier rather than a field or other construct. You follow this same pattern when you implement a collection-type property. However, a collection-type property introduces some complexity to the pattern whenever the type that is contained within the collection is itself a DependencyObject or Freezable derived class.