{"action":"opened","issue":{"url":"https://api.github.com/repos/reactiveui/ReactiveUI/issues/987","labels_url":"https://api.github.com/repos/reactiveui/ReactiveUI/issues/987/labels{/name}","comments_url":"https://api.github.com/repos/reactiveui/ReactiveUI/issues/987/comments","events_url":"https://api.github.com/repos/reactiveui/ReactiveUI/issues/987/events","html_url":"https://github.com/reactiveui/ReactiveUI/issues/987","id":118603829,"number":987,"title":"ItemChanging observable appears to fire *after* property is set","user":{"login":"gingermike","id":965703,"avatar_url":"https://avatars.githubusercontent.com/u/965703?v=3","gravatar_id":"","url":"https://api.github.com/users/gingermike","html_url":"https://github.com/gingermike","followers_url":"https://api.github.com/users/gingermike/followers","following_url":"https://api.github.com/users/gingermike/following{/other_user}","gists_url":"https://api.github.com/users/gingermike/gists{/gist_id}","starred_url":"https://api.github.com/users/gingermike/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/gingermike/subscriptions","organizations_url":"https://api.github.com/users/gingermike/orgs","repos_url":"https://api.github.com/users/gingermike/repos","events_url":"https://api.github.com/users/gingermike/events{/privacy}","received_events_url":"https://api.github.com/users/gingermike/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-11-24T13:00:09Z","updated_at":"2015-11-24T13:00:09Z","closed_at":null,"body":"Hi,\r\n\r\nI have a little project that I'm working on that has a feature to monitor the delta of changes in an underlying model. Specifically, I need the value before the item changed and after. The objects I'm monitoring are in a ReactiveList with ChangeTrackingEnabled set to true, though when I subscribe to the ItemChanging observable, I only seem to receive events *after* the model's property has changed. \r\n\r\nAm I doing something incredibly stupid here? \r\n\r\n```C#\r\n    private ReactiveList<Model> _list = new ReactiveList<Model> {ChangeTrackingEnabled = true}; \r\n\r\n        public MainWindowViewModel()\r\n        {\r\n            _list.Add(new Model {Test = \"abcd123\"});\r\n            _list.ItemChanging.Subscribe(x => Debug.WriteLine(\"Value before: \" + x.Sender.Test));\r\n            _list.ItemChanged.Subscribe(x => Debug.WriteLine(\"Value after: \" + x.Sender.Test));\r\n\r\n            ChangeModel = ReactiveCommand.Create();\r\n            ChangeModel.Subscribe(_ => _list[0].Test = \"blahblah\");\r\n        }\r\n\r\n        private ReactiveCommand<object> _changeModel;\r\n        public ReactiveCommand<object> ChangeModel\r\n        {\r\n            get { return _changeModel; }\r\n            set { this.RaiseAndSetIfChanged(ref _changeModel, value); }\r\n        }\r\n    }\r\n````\r\n\r\nThe output I get in the console:\r\n\r\n```\r\nValue before: blahblah\r\nValue after: blahblah\r\n````"}}