Work around broken ObservableForDP in WinRT

analogrelay · Jun 24, 2012 · de77e01 · de77e01
1 parent a626885
commit de77e01
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Showing 2 changed files with 43 additions and 22 deletions.
diff --git a/ReactiveUI.Routing/RoutedViewHost.cs b/ReactiveUI.Routing/RoutedViewHost.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Reactive.Linq;
 using System.Linq;
+using System.Reactive.Subjects;
 using System.Text;
 using System.Windows;
 using ReactiveUI;
@@ -33,7 +34,9 @@ public RoutingState Router {
             set { SetValue(RouterProperty, value); }
         }
         public static readonly DependencyProperty RouterProperty =
-            DependencyProperty.Register("Router", typeof(RoutingState), typeof(RoutedViewHost), new PropertyMetadata(null));
+            DependencyProperty.Register("Router", typeof(RoutingState), typeof(RoutedViewHost), new PropertyMetadata(null, routerChanged));
+
+        readonly Subject<RoutingState> routerChange;
 
         /// <summary>
         /// This content is displayed whenever there is no page currently
@@ -48,24 +51,34 @@ public object DefaultContent {
 
         public RoutedViewHost()
         {
-            this.ObservableFromDP(x => x.Router)
-                .Subscribe(x => {
-                    if (_inner != null) {
-                        _inner.Dispose();
-                        _inner = null;
-                    }
+            routerChange = new Subject<RoutingState>();
 
-                    _inner = x.Value.ViewModelObservable().Subscribe(vm => {
-                        if (vm == null) {
-                            Content = DefaultContent;
-                            return;
-                        }
+            routerChange.Subscribe(x => {
+                if (_inner != null) {
+                    _inner.Dispose();
+                    _inner = null;
+                }
+
+                _inner = x.ViewModelObservable().Subscribe(vm => {
+                    if (vm == null) {
+                        Content = DefaultContent;
+                        return;
+                    }
 
-                        var view = RxRouting.ResolveView(vm);
-                        view.ViewModel = vm;
-                        Content = view;
-                    });
+                    var view = RxRouting.ResolveView(vm);
+                    view.ViewModel = vm;
+                    Content = view;
                 });
+            });
         }
+
+        static void routerChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        {
+            // XXX: This is to work around the fact that ObservableFromDP 
+            // is broken in WinRT
+            var This = ((RoutedViewHost) dependencyObject);
+            This.routerChange.OnNext(This.Router);
+        }
+
     }
 }
diff --git a/ReactiveUI.Routing/ViewModelViewHost.cs b/ReactiveUI.Routing/ViewModelViewHost.cs
@@ -1,5 +1,7 @@
 using System;
+using System.Reactive;
 using System.Reactive.Linq;
+using System.Reactive.Subjects;
 using System.Windows;
 using ReactiveUI.Xaml;
 
@@ -27,7 +29,9 @@ public IReactiveNotifyPropertyChanged ViewModel {
             set { SetValue(ViewModelProperty, value); }
         }
         public static readonly DependencyProperty ViewModelProperty = 
-            DependencyProperty.Register("ViewModel", typeof(IReactiveNotifyPropertyChanged), typeof(ViewModelViewHost), new PropertyMetadata(null));
+            DependencyProperty.Register("ViewModel", typeof(IReactiveNotifyPropertyChanged), typeof(ViewModelViewHost), new PropertyMetadata(null, somethingChanged));
+
+        readonly Subject<Unit> updateViewModel = new Subject<Unit>();
 
         /// <summary>
         /// If no ViewModel is displayed, this content (i.e. a control) will be displayed.
@@ -37,14 +41,13 @@ public object DefaultContent {
             set { SetValue(DefaultContentProperty, value); }
         }
         public static readonly DependencyProperty DefaultContentProperty =
-            DependencyProperty.Register("DefaultContent", typeof(object), typeof(ViewModelViewHost), new PropertyMetadata(null));
+            DependencyProperty.Register("DefaultContent", typeof(object), typeof(ViewModelViewHost), new PropertyMetadata(null, somethingChanged));
 
         public ViewModelViewHost()
         {
-            var latestViewModel = Observable.CombineLatest(
-                this.ObservableFromDP(x => x.ViewModel).Select(x => x.Value).StartWith((IReactiveNotifyPropertyChanged)null),
-                this.ObservableFromDP(x => x.DataContext).Select(x => x.Value).OfType<IReactiveNotifyPropertyChanged>().StartWith((IReactiveNotifyPropertyChanged)null),
-                (vm, dc) => vm ?? dc);
+            var latestViewModel = updateViewModel
+                .Select(_ => (IReactiveNotifyPropertyChanged)(ViewModel ?? DataContext))
+                .StartWith((IReactiveNotifyPropertyChanged) null);
 
             latestViewModel.Subscribe(vm => {
                 if (vm == null) {
@@ -57,5 +60,10 @@ public ViewModelViewHost()
                 Content = view;
             });
         }
+
+        static void somethingChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        {
+            ((ViewModelViewHost)dependencyObject).updateViewModel.OnNext(Unit.Default);
+        }
     }
 }