def __init__(self, getter):
def newgetter(slf):
#return None when the property does not exist yet
try:
return getter(slf)
except AttributeError:
return None
getter = clrtype.accepts()(getter)
clrtype.propagate_attributes(getter, newgetter)
super(notify_property, self).__init__(newgetter)
def setter(self, setter):
def newsetter(slf, newvalue):
# do not change value if the new value is the same
# trigger PropertyChanged event when value changes
oldvalue = self.fget(slf)
if oldvalue != newvalue:
setter(slf, newvalue)
slf.OnPropertyChanged(setter.__name__)
setter = clrtype.returns()(setter)
clrtype.propagate_attributes(setter, newsetter)
return property(
fget=self.fget,
fset=newsetter,
fdel=self.fdel,
doc=self.__doc__)