Binding static property and implementing INotifyPropertyChanged

Question

I\'m trying to bind a static property of some class to some control. I\'ve tryied a few implementation but each has its problem:

All examples use the next XAML:

Answer 1

Using a singleton is going to be the easiest and cleanest to implement. If you want to go the hard way without using a singleton you can use the following.

Create a static PropertyChangedEventHandler that gets called from your static property. When you create a new instance of your class, register to receive a call back from the static event. When you get the callback, call OnPropertyChanged("text"). The BIG problem with this is you need to use a WeakReference when you register for the static event. Otherwise your object will stay around forever. I skipped this step in the code.

The reason you need to forward to the instance-event is because who ever registered the NotifyPropertyChanged needs to know who the 'sender' (ie the instance of foo1 with the instance-property on it)

public class foo1 : System.ComponentModel.INotifyPropertyChanged
{
    // static property
    private static string _text = "static string";
    public static string static_text
    {
        get
        {
            return _text;
        }
        set
        {
            _text = value;
            OnStaticPropertyChanged("static_text");
        }
    }
    private static System.ComponentModel.PropertyChangedEventHandler staticpropChanged;
    static protected void OnStaticPropertyChanged(string pname)
    {
        System.ComponentModel.PropertyChangedEventArgs e = new System.ComponentModel.PropertyChangedEventArgs(pname);
        System.ComponentModel.PropertyChangedEventHandler h = staticpropChanged;
        if (h != null)
            h(null, e);

    }
    public foo1()
    {
        // really should use a weakreference here.. but leaving it out
        // for simplicity
        staticpropChanged += foo1_staticpropChanged;
    }

    void foo1_staticpropChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
    {
        // map the static name to the instance name
        if(e.PropertyName == "static_text") OnPropertyChanged("text");
    }
    // instance-property forwards to static
    public string text
    {
        get { return foo1.static_text; }
        set { foo1.static_text = value; }
    }