public MainWindowViewModel()
{
#region Test
AddMemberName = new ReactiveProperty <string>(string.Empty);
AddMemberIsLong = new ReactiveProperty <bool>(false);
AddMemberIsSelected = new ReactiveProperty <bool>(false);
RemoveMemberName = new ReactiveProperty <string>(string.Empty);
AddMemberCommand = new AsyncReactiveCommand();
AddMemberCommand.Subscribe(_ => AddMember(AddMemberName.Value, AddMemberIsLong.Value, AddMemberIsSelected.Value));
RemoveMemberCommand = new ReactiveCommand();
RemoveMemberCommand.Subscribe(_ => RemoveMember(RemoveMemberName.Value));
ClearMemberCommand = Members.ObserveProperty(x => x.Count).Select(x => 0 < x).ToReactiveCommand();
ClearMemberCommand.Subscribe(_ => ClearMember());
#endregion
PopulateMembers();
Members
.ObserveElementProperty(x => x.IsLong)
.Where(x => x.Value)
.Subscribe(x => ShowName(x.Instance));
Members
.ObserveElementObservableProperty(x => x.IsSelected)
.Where(x => x.Value)
.Subscribe(x => ShowName(x.Instance));
// IsAllLong: Original
IsAllLong = Members
.ObserveElementProperty(x => x.IsLong)
.Select(_ => Members.All(x => x.IsLong))
.ToReactiveProperty();
// IsAllLong: Alternative
IFilteredReadOnlyObservableCollection <MemberViewModel> membersNotLong = Members
.ToFilteredReadOnlyObservableCollection(x => !x.IsLong);
IsAllLong = membersNotLong
.CollectionChangedAsObservable()
.Select(_ => Members.Any() && (0 == membersNotLong.Count))
.ToReactiveProperty();
// IsAnySelected: Original
IsAnySelected = Members
.ObserveElementObservableProperty(x => x.IsSelected)
.Select(_ => Members.Any(x => x.IsSelected.Value))
.ToReactiveProperty();
// IsAnySelected: Alternative 1
List <MemberViewModel> membersSelected = new List <MemberViewModel>();
IObservable <bool> elementPropertyChanged = Members
.ObserveElementObservableProperty(x => x.IsSelected)
.Do(x =>
{
if (!x.Value)
{
membersSelected.Remove(x.Instance);
}
else if (!membersSelected.Contains(x.Instance))
{
membersSelected.Add(x.Instance);
}
})
.Select(_ => 0 < membersSelected.Count);
IObservable <bool> collectionChanged = Members
.CollectionChangedAsObservable()
.Where(x => x.Action != NotifyCollectionChangedAction.Move)
.Do(x =>
{
switch (x.Action)
{
case NotifyCollectionChangedAction.Add:
case NotifyCollectionChangedAction.Remove:
case NotifyCollectionChangedAction.Replace:
if (x.OldItems != null)
{
foreach (var instance in x.OldItems.Cast <MemberViewModel>())
{
membersSelected.Remove(instance);
}
}
if (x.NewItems != null)
{
foreach (var instance in x.NewItems.Cast <MemberViewModel>())
{
if (membersSelected.Contains(instance))
{
continue;
}
if (instance.IsSelected.Value)
{
membersSelected.Add(instance);
}
}
}
break;
case NotifyCollectionChangedAction.Reset:
membersSelected.Clear();
break;
}
})
.Select(_ => 0 < membersSelected.Count);
IsAnySelected = Observable.Merge(elementPropertyChanged, collectionChanged)
.ToReactiveProperty();
// IsAnySelected: Alternative 2
IsAnySelected = Members
.ObserveElementBooleanObservableProperty(x => x.IsSelected)
.Select(x => 0 < x.Count)
.ToReactiveProperty();
// IsAnySelected: Alternative 3
IsAnySelected = Members
.ObserveElementFilteredObservableProperty(x => x.IsSelected, x => x)
.Select(x => 0 < x.Count)
.ToReactiveProperty();
}
