Restore missing DefaultContentProperty prop

src/Avalonia.ReactiveUI/RoutedViewHost.cs

@@ -64,6 +64,12 @@ namespace Avalonia.ReactiveUI
         public static readonly StyledProperty<string?> ViewContractProperty =
             AvaloniaProperty.Register<RoutedViewHost, string?>(nameof(ViewContract));
 
+        /// <summary>
+        /// <see cref="AvaloniaProperty"/> for the <see cref="DefaultContent"/> property.
+        /// </summary>
+        public static readonly StyledProperty<object?> DefaultContentProperty =
+            ViewModelViewHost.DefaultContentProperty.AddOwner<RoutedViewHost>();
+
         /// <summary>
         /// Initializes a new instance of the <see cref="RoutedViewHost"/> class.
         /// </summary>
@@ -106,6 +112,15 @@ namespace Avalonia.ReactiveUI
             set => SetValue(ViewContractProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the content displayed whenever there is no page currently routed.
+        /// </summary>
+        public object? DefaultContent
+        {
+            get => GetValue(DefaultContentProperty);
+            set => SetValue(DefaultContentProperty, value);
+        }
+
         /// <summary>
         /// Gets or sets the ReactiveUI view locator used by this router.
         /// </summary>

src/Avalonia.ReactiveUI/ViewModelViewHost.cs

@@ -1,5 +1,8 @@
 using System;
 using System.Reactive.Disposables;
+
+using Avalonia.Controls;
+
 using ReactiveUI;
 using Splat;
 
@@ -24,6 +27,12 @@ namespace Avalonia.ReactiveUI
         public static readonly StyledProperty<string?> ViewContractProperty =
             AvaloniaProperty.Register<ViewModelViewHost, string?>(nameof(ViewContract));
 
+        /// <summary>
+        /// <see cref="AvaloniaProperty"/> for the <see cref="DefaultContent"/> property.
+        /// </summary>
+        public static readonly StyledProperty<object?> DefaultContentProperty =
+            AvaloniaProperty.Register<ViewModelViewHost, object?>(nameof(DefaultContent));
+
         /// <summary>
         /// Initializes a new instance of the <see cref="ViewModelViewHost"/> class.
         /// </summary>
@@ -55,6 +64,15 @@ namespace Avalonia.ReactiveUI
             set => SetValue(ViewContractProperty, value);
         }
 
+        /// <summary>
+        /// Gets or sets the content displayed whenever there is no page currently routed.
+        /// </summary>
+        public object? DefaultContent
+        {
+            get => GetValue(DefaultContentProperty);
+            set => SetValue(DefaultContentProperty, value);
+        }
+
         /// <summary>
         /// Gets or sets the view locator.
         /// </summary>