public static ObservableValue <int> CreateCounterProperty(
this BaseViewModel viewModel,
string propertyName,
Func <IObservable <Unit> > reset,
int initialValue = 0,
int minimum = 0,
int?maximum = null)
{
return(viewModel.CreateActiveProperty(
propertyName,
"Increase" + propertyName,
"Decrease" + propertyName,
(increase, decrease) => Observable
.Merge(
reset().Select(_ => 0),
increase.Select(_ => 1),
decrease.Select(_ => - 1))
.Scan(initialValue, (value, effect) => (effect == 0)
? initialValue
: Math.Min(maximum ?? int.MaxValue, Math.Max(0, value + effect))),
initialValue));
}
