Databinding to index property

I have a control bind to an index property of an object which implements INotifyPropertyChanged.

The problem is, I don't know how to notify the property changed signal for that particular index string.

I was told that I can use OnPropertyChanged(""开发者_如何学C) to notify the whole object need to be changed.

But what I need is something like OnPropertyChanged("Some index property string").

Is there anyway to do it?

Many thanks.

ps:

What I am trying to do is apply MVVM pattern. I use a viewmodel class to wrap a normal POCO object. So when I bind, I bind to the [index property], so that I can notify changed. This method saves me from:

1. wrap the inner domain POCO object for EVERY property I need.
2. notify property changed in every wrapped property.

CODE

public class ViewModelEx<T_Self, T_Core> : ViewModelEx<T_Self> where T_Self : ViewModelEx<T_Self, T_Core>
{
private static Type _s_coreType = typeof(T_Core);
private static Dictionary<string, PropertyInfo> _s_corePropInfos = new Dictionary<string, PropertyInfo>();

private static PropertyInfo GetPropertyInfo(string prop)
{
    if (_s_corePropInfos.ContainsKey(prop) == false)
        _s_corePropInfos.Add(prop, _s_coreType.GetProperty(prop));

    return _s_corePropInfos[prop];
}

public T_Core Core { get; set; }

public object this[string propName]
{
    get
    {
        return GetPropertyInfo(propName).GetValue(Core, null);
    }
    set
    {
        GetPropertyInfo(propName).SetValue(Core, value, null);
        IsModified = true;
        //RaisePropertyChanged(propName);
        RaisePropertyChanged("");
    }
}

public R Val<R>(Expression<Func<T_Core, R>> expr)
{
    return (R)this[Core.GetPropertyStr(expr)];
}

public void Val<R>(Expression<Func<T_Core, R>> expr, R val)
{
    this[Core.GetPropertyStr(expr)] = val;
}

You cannot create notifications for specific index bindings in WPF, you can only notify all index-bindings:

RaisePropertyChanged(Binding.IndexerName);

Which should be the same as:

RaisePropertyChanged("Item[]");

You could override this string using the IndexerNameAttribute.

(In Silverlight you can actually specify an index inside the brackets to only affect that specific binding.)