/// <summary>
/// Creates a special storage locaiton wrapped in a BindingValue, which supports change notification.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="initialValue">The initial value to which the storage location is initialized.</param>
/// <param name="name"></param>
/// <returns></returns>
public static BindingValue <T> Variable <T>(T initialValue, string name = "?")
{
var storage = initialValue;
BindingValue <T> bindingValue = null;
Action <T> setter = v => {
storage = v;
bindingValue.NotifyChange();
};
Func <T> getter = () => storage;
bindingValue = new BindingValue <T>(setter, getter, name);
return(bindingValue);
}
/// <summary>
/// Creates a BindingValue from an expression that accesses a property or field.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expr"></param>
/// <param name="notifier"></param>
/// <returns></returns>
public static BindingValue <T> Member <T>(Expression <Func <T> > expr, INotifyPropertyChanged notifier = null)
{
var accessor = ReflectHelper.AnalyzeMember(expr);
var instance = accessor.InstanceGetter();
var instanceName = ReflectHelper.TryGetName(instance);
notifier = notifier ?? accessor.InstanceGetter() as INotifyPropertyChanged;
var bindingValue = new BindingValue <T>(accessor.Setter, accessor.Getter, $"{instanceName ?? "?"}.{accessor.TopmostMember.Name}");
if (notifier != null)
{
notifier.PropertyChanged += (sender, e) => {
if (e.PropertyName == accessor.TopmostMember.Name)
{
bindingValue.NotifyChange();
}
};
}
return(bindingValue);
}
