Question

My goal is to bind to a set of objects in WPF. I first tried to use generics but horribly failed at it. Since I can’t cast generic properties to INotifyProperty interfaces, to hook up the changedevent.

So I came up with this class to use as an object in my BindingList. ( Yes, I need those to notify me when an object within the list changes ). So I need your opinion, improvements on my code.

public class GPair : ObservableObject
{
    public GPair()
    {
    }

    private ObservableObject _first;
    public ObservableObject First
    {
        get
        {
            return this._first;
        }
        set
        {
            this._first = value;
            ((ObservableObject)value).PropertyChanged +=new PropertyChangedEventHandler(First_PropertyChanged);
            RaisePropertyChanged("First");
        }
    }
    private ObservableObject _second;
    public ObservableObject Second
    {
        get
        {
            return this._second;
        }
        set
        {
            this._second = value;
            ((ObservableObject)value).PropertyChanged += new PropertyChangedEventHandler(Second_PropertyChanged);
            RaisePropertyChanged("Second");
        }
    }

    private void First_PropertyChanged(object sender, PropertyChangedEventArgs args)
    {
        RaisePropertyChanged("First");
    }
    private void Second_PropertyChanged(object sender, PropertyChangedEventArgs args)
    {
        RaisePropertyChanged("Second");
    }
}

The ObservableObject is just a helperclass that implements the INotifyPropertyChanged.

This piece of code allows me couple two objects in a binding… The Binding itself would look like this:

<StackPanel Orientation="Horizontal">
    <TextBlock Text="{Binding Path=First.ObjectPropertie}" />
    <TextBlock Text="{Binding Path=Second.ObjectPropertie}" />
</StackPanel>

Any opinions or improvements??

Kind regards!

Answer 1

I don’t fully get what you are trying to achieve, but the GPair class looks odd

What about having something like this?

  public class ObservablePair : INotifyPropertyChanged
  {
        public event PropertyChangedEventHandler PropertyChanged;

        private MyObject m_First;
        public MyObject First
        {
            get { return m_First; }
            set
            {
                m_First = value;
                OnPropertyChanged("First");
            }

        }

        private MyObject m_Second;
        public MyObject Second
        {
            get { return m_Second; }
            set
            {
                m_Second = value;
                OnPropertyChanged("Second");
            }
        }

        public void OnPropertyChanged(string propertyName)
        {
                PropertyChangedEventHandler handler = PropertyChanged;
                if (handler != null) handler(this, new 
                    PropertyChangedEventArgs(propertyName)); ;
        }
 }

HTH