From 2b6c74148eb252d1d21fd9c8fd819ceed8b368a5 Mon Sep 17 00:00:00 2001
From: artyom <worldbeater-dev@yandex.ru>
Date: Fri, 23 Oct 2020 12:11:18 +0300
Subject: [PATCH] Use ObservableForProperty() instead of WhenAny() with Skip()

---
 src/Avalonia.ReactiveUI/ReactiveUserControl.cs | 13 +++++++------
 src/Avalonia.ReactiveUI/ReactiveWindow.cs      | 13 +++++++------
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/src/Avalonia.ReactiveUI/ReactiveUserControl.cs b/src/Avalonia.ReactiveUI/ReactiveUserControl.cs
index 2cf1f1e678..31f4691c90 100644
--- a/src/Avalonia.ReactiveUI/ReactiveUserControl.cs
+++ b/src/Avalonia.ReactiveUI/ReactiveUserControl.cs
@@ -25,13 +25,14 @@ namespace Avalonia.ReactiveUI
         /// </summary>
         public ReactiveUserControl()
         {
+            // This WhenActivated block calls ViewModel's WhenActivated
+            // block if the ViewModel implements IActivatableViewModel.
             this.WhenActivated(disposables => { });
-            this.WhenAnyValue(x => x.ViewModel)
-                .Skip(1)
-                .Subscribe(model => DataContext = model);
-            this.WhenAnyValue(x => x.DataContext)
-                .Skip(1)
-                .Subscribe(context => ViewModel = context as TViewModel);
+
+            this.ObservableForProperty(x => x.ViewModel, false, true)
+                .Subscribe(args => DataContext = args.Value);
+            this.ObservableForProperty(x => x.DataContext, false, true)
+                .Subscribe(args => ViewModel = args.Value as TViewModel);
         }
 
         /// <summary>
diff --git a/src/Avalonia.ReactiveUI/ReactiveWindow.cs b/src/Avalonia.ReactiveUI/ReactiveWindow.cs
index 77ffe04c5d..1204266b63 100644
--- a/src/Avalonia.ReactiveUI/ReactiveWindow.cs
+++ b/src/Avalonia.ReactiveUI/ReactiveWindow.cs
@@ -25,13 +25,14 @@ namespace Avalonia.ReactiveUI
         /// </summary>
         public ReactiveWindow()
         {
+            // This WhenActivated block calls ViewModel's WhenActivated
+            // block if the ViewModel implements IActivatableViewModel.
             this.WhenActivated(disposables => { });
-            this.WhenAnyValue(x => x.ViewModel)
-                .Skip(1)
-                .Subscribe(model => DataContext = model);
-            this.WhenAnyValue(x => x.DataContext)
-                .Skip(1)
-                .Subscribe(context => ViewModel = context as TViewModel);
+
+            this.ObservableForProperty(x => x.ViewModel, false, true)
+                .Subscribe(args => DataContext = args.Value);
+            this.ObservableForProperty(x => x.DataContext, false, true)
+                .Subscribe(args => ViewModel = args.Value as TViewModel);
         }
             
         /// <summary>