Programmatic type-safe bindings

ObservableDependencyValue.cs

using System;
using System.Linq.Expressions;
using System.Windows;
using System.Windows.Data;

namespace MonkeyBusters
{
    public static class ObservableDependencyValue
    {
        public static ObservableDependencyValue<T> Create<T>(Expression<Func<T>> expr, BindingMode mode = BindingMode.OneWay)
        {
            return new ObservableDependencyValue<T>().Bind(expr, mode);
        }
    }

    public class ObservableDependencyValue<T> : DependencyObject
    {
        #region T ObservableDependencyValue<T>.Value = default(T)
        #region Boilerplate

        public T Value
        {
            get { return (T)GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }

        public static readonly DependencyProperty ValueProperty =
            DependencyProperty.Register("Value", typeof(T), typeof(ObservableDependencyValue<T>), new PropertyMetadata(default(T), StaticHandleValueChanged));

        static void StaticHandleValueChanged(DependencyObject self, DependencyPropertyChangedEventArgs args)
        {
            ((ObservableDependencyValue<T>)self).HandleValueChanged((T)args.OldValue, (T)args.NewValue);
        }

        #endregion

        void HandleValueChanged(T oldValue, T value)
        {
            Notify();
        }
        #endregion

        public ObservableDependencyValue()
        {
        }

        public ObservableDependencyValue(BindingBase bindingBase)
        {
            Bind(bindingBase);
        }

        public ObservableDependencyValue<T> Bind(BindingBase bindingBase)
        {
            BindingOperations.SetBinding(this, ValueProperty, bindingBase);

            return this;
        }

        public ObservableDependencyValue<T> Bind(Expression<Func<T>> expr, BindingMode mode = BindingMode.OneWay)
        {
            var path = RootedPropertyPath.Create(expr);

            return Bind(new Binding(path.Path) { Source = path.Target, Mode = mode });
        }

        public void Notify()
        {
            if (ValueChanged != null) ValueChanged(Value);
        }

        public event Action<T> ValueChanged;
    }
}