public NotifierEntry(Notifier notifier, NotifierProperty property, Func <object, object> getter)
{
Notifier = notifier;
Property = property;
Getter = getter;
Value = getter(null);
}
public bool Set <T>(object target, T value, NotifierProperty property, Action <T, T> postUpdateAction = null)
{
bool isnew = false;
var entry = Entries.GetOrAdd(property, (oldValue) =>
{
isnew = true;
return(new NotifierEntry(this, property, n => value));
}
);
if (isnew)
{
OnPropertyChanged(new NotifierPropertyChangedEventArgs(property.Name, default(T), value));
return(true);
}
var old = entry.GetValue <T>();
if (entry.SetValue(value))
{
postUpdateAction?.Invoke(old, value);
OnPropertyChanged(new NotifierPropertyChangedEventArgs(property.Name, old, value));
return(true);
}
return(false);
}
public bool Update(NotifierProperty property)
{
if (Entries.TryGetValue(property, out var entry))
{
var old = entry.GetValue <object>();
if (entry.Update())
{
OnPropertyChanged(new NotifierPropertyChangedEventArgs(property.Name, old, entry.GetValue <object>()));
return(true);
}
}
return(false);
}
public T Get <T>(object target, Func <T, T> getter, NotifierProperty property, Action postUpdateAction = null)
{
try
{
return(Entries.GetOrAdd(property,
e => new NotifierEntry(this, property, a => getter.Invoke((T)(a ?? default(T))))).GetValue <T>());
}
catch (PropertyNotReady ex)
{
if (Entries.TryRemove(property, out var e))
{
}
;
return((T)ex.ReturnValue);
}
catch (NullReferenceException ex)
{
if (Entries.TryRemove(property, out var e))
{
}
return(default(T));
}
}
public bool IsSet(NotifierProperty property) => Entries.ContainsKey(property);