The Great Interface Removal Part I

samples/ControlCatalog/ViewModels/TransitioningContentControlPageViewModel.cs

@@ -293,10 +293,10 @@ public async Task Start(Visual? from, Visual? to, bool forward, CancellationToke
         /// <remarks>
         /// Any one of the parameters may be null, but not both.
         /// </remarks>
-        private static IVisual GetVisualParent(IVisual? from, IVisual? to)
+        private static Visual GetVisualParent(Visual? from, Visual? to)
         {
-            var p1 = (from ?? to)!.VisualParent;
-            var p2 = (to ?? from)!.VisualParent;
+            var p1 = (from ?? to)!.GetVisualParent();
+            var p2 = (to ?? from)!.GetVisualParent();
 
             if (p1 != null && p2 != null && p1 != p2)
             {

src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs

@@ -109,7 +109,7 @@ public IRenderer CreateRenderer(IRenderRoot root) =>
                 ? new CompositingRenderer(root, AndroidPlatform.Compositor)
                 : AndroidPlatform.Options.UseDeferredRendering
                     ? new DeferredRenderer(root, AvaloniaLocator.Current.GetRequiredService<IRenderLoop>()) { RenderOnlyOnRenderThread = true }
-                    : new ImmediateRenderer(root);
+                    : new ImmediateRenderer((Visual)root);
 
         public virtual void Hide()
         {

src/Avalonia.Base/Animation/PageSlide.cs

@@ -157,7 +157,7 @@ public virtual async Task Start(Visual? from, Visual? to, bool forward, Cancella
         /// <remarks>
         /// Any one of the parameters may be null, but not both.
         /// </remarks>
-        protected static IVisual GetVisualParent(IVisual? from, IVisual? to)
+        protected static Visual GetVisualParent(Visual? from, Visual? to)
         {
             var p1 = (from ?? to)!.VisualParent;
             var p2 = (to ?? from)!.VisualParent;

src/Avalonia.Base/AttachedProperty.cs

@@ -34,7 +34,7 @@ public AttachedProperty(
         /// </summary>
         /// <typeparam name="TOwner">The owner type.</typeparam>
         /// <returns>The property.</returns>
-        public new AttachedProperty<TValue> AddOwner<TOwner>() where TOwner : IAvaloniaObject
+        public new AttachedProperty<TValue> AddOwner<TOwner>() where TOwner : AvaloniaObject
         {
             AvaloniaPropertyRegistry.Instance.Register(typeof(TOwner), this);
             return this;

src/Avalonia.Base/AvaloniaObject.cs

@@ -16,7 +16,7 @@ namespace Avalonia
     /// <remarks>
     /// This class is analogous to DependencyObject in WPF.
     /// </remarks>
-    public class AvaloniaObject : IAvaloniaObject, IAvaloniaObjectDebug, INotifyPropertyChanged
+    public class AvaloniaObject : IAvaloniaObjectDebug, INotifyPropertyChanged
     {
         private readonly ValueStore _values;
         private AvaloniaObject? _inheritanceParent;

src/Avalonia.Base/AvaloniaObjectExtensions.cs

@@ -36,7 +36,7 @@ public static IBinding ToBinding<T>(this IObservable<T> source)
         /// <remarks>
         /// The subscription to <paramref name="o"/> is created using a weak reference.
         /// </remarks>
-        public static IObservable<object?> GetObservable(this IAvaloniaObject o, AvaloniaProperty property)
+        public static IObservable<object?> GetObservable(this AvaloniaObject o, AvaloniaProperty property)
         {
             return new AvaloniaPropertyObservable<object?>(
                 o ?? throw new ArgumentNullException(nameof(o)), 
@@ -56,7 +56,7 @@ public static IBinding ToBinding<T>(this IObservable<T> source)
         /// <remarks>
         /// The subscription to <paramref name="o"/> is created using a weak reference.
         /// </remarks>
-        public static IObservable<T> GetObservable<T>(this IAvaloniaObject o, AvaloniaProperty<T> property)
+        public static IObservable<T> GetObservable<T>(this AvaloniaObject o, AvaloniaProperty<T> property)
         {
             return new AvaloniaPropertyObservable<T>(
                 o ?? throw new ArgumentNullException(nameof(o)),
@@ -76,7 +76,7 @@ public static IObservable<T> GetObservable<T>(this IAvaloniaObject o, AvaloniaPr
         /// The subscription to <paramref name="o"/> is created using a weak reference.
         /// </remarks>
         public static IObservable<BindingValue<object?>> GetBindingObservable(
-            this IAvaloniaObject o,
+            this AvaloniaObject o,
             AvaloniaProperty property)
         {
             return new AvaloniaPropertyBindingObservable<object?>(
@@ -98,7 +98,7 @@ public static IObservable<T> GetObservable<T>(this IAvaloniaObject o, AvaloniaPr
         /// The subscription to <paramref name="o"/> is created using a weak reference.
         /// </remarks>
         public static IObservable<BindingValue<T>> GetBindingObservable<T>(
-            this IAvaloniaObject o,
+            this AvaloniaObject o,
             AvaloniaProperty<T> property)
         {
             return new AvaloniaPropertyBindingObservable<T>(
@@ -115,11 +115,11 @@ public static IObservable<BindingValue<T>> GetBindingObservable<T>(
         /// <param name="property">The property.</param>
         /// <returns>
         /// An observable which when subscribed pushes the property changed event args
-        /// each time a <see cref="IAvaloniaObject.PropertyChanged"/> event is raised
+        /// each time a <see cref="AvaloniaObject.PropertyChanged"/> event is raised
         /// for the specified property.
         /// </returns>
         public static IObservable<AvaloniaPropertyChangedEventArgs> GetPropertyChangedObservable(
-            this IAvaloniaObject o,
+            this AvaloniaObject o,
             AvaloniaProperty property)
         {
             return new AvaloniaPropertyChangedObservable(
@@ -140,7 +140,7 @@ public static IObservable<AvaloniaPropertyChangedEventArgs> GetPropertyChangedOb
         /// property.
         /// </returns>
         public static ISubject<object?> GetSubject(
-            this IAvaloniaObject o,
+            this AvaloniaObject o,
             AvaloniaProperty property,
             BindingPriority priority = BindingPriority.LocalValue)
         {
@@ -163,7 +163,7 @@ public static IObservable<AvaloniaPropertyChangedEventArgs> GetPropertyChangedOb
         /// property.
         /// </returns>
         public static ISubject<T> GetSubject<T>(
-            this IAvaloniaObject o,
+            this AvaloniaObject o,
             AvaloniaProperty<T> property,
             BindingPriority priority = BindingPriority.LocalValue)
         {
@@ -185,7 +185,7 @@ public static ISubject<T> GetSubject<T>(
         /// property.
         /// </returns>
         public static ISubject<BindingValue<object?>> GetBindingSubject(
-            this IAvaloniaObject o,
+            this AvaloniaObject o,
             AvaloniaProperty property,
             BindingPriority priority = BindingPriority.LocalValue)
         {
@@ -214,7 +214,7 @@ public static ISubject<T> GetSubject<T>(
         /// property.
         /// </returns>
         public static ISubject<BindingValue<T>> GetBindingSubject<T>(
-            this IAvaloniaObject o,
+            this AvaloniaObject o,
             AvaloniaProperty<T> property,
             BindingPriority priority = BindingPriority.LocalValue)
         {
@@ -241,7 +241,7 @@ public static ISubject<BindingValue<T>> GetBindingSubject<T>(
         /// A disposable which can be used to terminate the binding.
         /// </returns>
         public static IDisposable Bind<T>(
-            this IAvaloniaObject target,
+            this AvaloniaObject target,
             AvaloniaProperty<T> property,
             IObservable<BindingValue<T>> source,
             BindingPriority priority = BindingPriority.LocalValue)
@@ -250,17 +250,12 @@ public static IDisposable Bind<T>(
             property = property ?? throw new ArgumentNullException(nameof(property));
             source = source ?? throw new ArgumentNullException(nameof(source));
 
-            if (target is AvaloniaObject ao)
+            return property switch
             {
-                return property switch
-                {
-                    StyledPropertyBase<T> styled => ao.Bind(styled, source, priority),
-                    DirectPropertyBase<T> direct => ao.Bind(direct, source),
-                    _ => throw new NotSupportedException("Unsupported AvaloniaProperty type."),
-                };
-            }
-
-            throw new NotSupportedException("Custom implementations of IAvaloniaObject not supported.");
+                StyledPropertyBase<T> styled => target.Bind(styled, source, priority),
+                DirectPropertyBase<T> direct => target.Bind(direct, source),
+                _ => throw new NotSupportedException("Unsupported AvaloniaProperty type."),
+            };
         }
 
         /// <summary>
@@ -274,22 +269,17 @@ public static IDisposable Bind<T>(
         /// A disposable which can be used to terminate the binding.
         /// </returns>
         public static IDisposable Bind<T>(
-            this IAvaloniaObject target,
+            this AvaloniaObject target,
             AvaloniaProperty<T> property,
             IObservable<T> source,
             BindingPriority priority = BindingPriority.LocalValue)
         {
-            if (target is AvaloniaObject ao)
+            return property switch
             {
-                return property switch
-                {
-                    StyledPropertyBase<T> styled => ao.Bind(styled, source, priority),
-                    DirectPropertyBase<T> direct => ao.Bind(direct, source),
-                    _ => throw new NotSupportedException("Unsupported AvaloniaProperty type."),
-                };
-            }
-
-            throw new NotSupportedException("Custom implementations of IAvaloniaObject not supported.");
+                StyledPropertyBase<T> styled => target.Bind(styled, source, priority),
+                DirectPropertyBase<T> direct => target.Bind(direct, source),
+                _ => throw new NotSupportedException("Unsupported AvaloniaProperty type."),
+            };
         }
 
         /// <summary>
@@ -306,7 +296,7 @@ public static IDisposable Bind<T>(
         /// </param>
         /// <returns>An <see cref="IDisposable"/> which can be used to cancel the binding.</returns>
         public static IDisposable Bind(
-            this IAvaloniaObject target,
+            this AvaloniaObject target,
             AvaloniaProperty property,
             IBinding binding,
             object? anchor = null)
@@ -340,23 +330,17 @@ public static IDisposable Bind(
         /// <param name="target">The object.</param>
         /// <param name="property">The property.</param>
         /// <returns>The value.</returns>
-        public static T GetValue<T>(this IAvaloniaObject target, AvaloniaProperty<T> property)
+        public static T GetValue<T>(this AvaloniaObject target, AvaloniaProperty<T> property)
         {
             target = target ?? throw new ArgumentNullException(nameof(target));
             property = property ?? throw new ArgumentNullException(nameof(property));
 
-            if (target is AvaloniaObject ao)
+            return property switch
             {
-                return property switch
-                {
-                    StyledPropertyBase<T> styled => ao.GetValue(styled),
-                    DirectPropertyBase<T> direct => ao.GetValue(direct),
-                    _ => throw new NotSupportedException("Unsupported AvaloniaProperty type.")
-                };
-
-            }
-
-            throw new NotSupportedException("Custom implementations of IAvaloniaObject not supported.");
+                StyledPropertyBase<T> styled => target.GetValue(styled),
+                DirectPropertyBase<T> direct => target.GetValue(direct),
+                _ => throw new NotSupportedException("Unsupported AvaloniaProperty type.")
+            };
         }
 
         /// <summary>
@@ -372,15 +356,13 @@ public static T GetValue<T>(this IAvaloniaObject target, AvaloniaProperty<T> pro
         /// For direct properties returns the current value of the property.
         /// </remarks>
         public static object? GetBaseValue(
-            this IAvaloniaObject target,
+            this AvaloniaObject target,
             AvaloniaProperty property)
         {
             target = target ?? throw new ArgumentNullException(nameof(target));
             property = property ?? throw new ArgumentNullException(nameof(property));
 
-            if (target is AvaloniaObject ao)
-                return property.RouteGetBaseValue(ao);
-            throw new NotSupportedException("Custom implementations of IAvaloniaObject not supported.");
+            return property.RouteGetBaseValue(target);
         }
 
         /// <summary>
@@ -396,24 +378,18 @@ public static T GetValue<T>(this IAvaloniaObject target, AvaloniaProperty<T> pro
         /// For direct properties returns the current value of the property.
         /// </remarks>
         public static Optional<T> GetBaseValue<T>(
-            this IAvaloniaObject target,
+            this AvaloniaObject target,
             AvaloniaProperty<T> property)
         {
             target = target ?? throw new ArgumentNullException(nameof(target));
             property = property ?? throw new ArgumentNullException(nameof(property));
 
-            if (target is AvaloniaObject ao)
+            return property switch
             {
-                return property switch
-                {
-                    StyledPropertyBase<T> styled => ao.GetBaseValue(styled),
-                    DirectPropertyBase<T> direct => ao.GetValue(direct),
-                    _ => throw new NotSupportedException("Unsupported AvaloniaProperty type.")
-                };
-
-            }
-
-            throw new NotSupportedException("Custom implementations of IAvaloniaObject not supported.");
+                StyledPropertyBase<T> styled => target.GetBaseValue(styled),
+                DirectPropertyBase<T> direct => target.GetValue(direct),
+                _ => throw new NotSupportedException("Unsupported AvaloniaProperty type.")
+            };
         }
 
         /// <summary>
@@ -474,7 +450,7 @@ public BindingAdaptor(IObservable<object?> source)
             }
 
             public InstancedBinding? Initiate(
-                IAvaloniaObject target,
+                AvaloniaObject target,
                 AvaloniaProperty? targetProperty,
                 object? anchor = null,
                 bool enableDataValidation = false)

src/Avalonia.Base/AvaloniaProperty.cs

@@ -38,7 +38,7 @@ protected AvaloniaProperty(
             Type valueType,
             Type ownerType,
             AvaloniaPropertyMetadata metadata,
-            Action<IAvaloniaObject, bool>? notifying = null)
+            Action<AvaloniaObject, bool>? notifying = null)
         {
             _ = name ?? throw new ArgumentNullException(nameof(name));
 
@@ -145,7 +145,7 @@ protected AvaloniaProperty(
         /// will be true before the property change notifications are sent and false afterwards. This
         /// callback is intended to support Control.IsDataContextChanging.
         /// </remarks>
-        public Action<IAvaloniaObject, bool>? Notifying { get; }
+        public Action<AvaloniaObject, bool>? Notifying { get; }
 
         /// <summary>
         /// Gets the integer ID that represents this property.
@@ -238,9 +238,9 @@ public static StyledProperty<TValue> Register<TOwner, TValue>(
             bool inherits = false,
             BindingMode defaultBindingMode = BindingMode.OneWay,
             Func<TValue, bool>? validate = null,
-            Func<IAvaloniaObject, TValue, TValue>? coerce = null,
-            Action<IAvaloniaObject, bool>? notifying = null)
-                where TOwner : IAvaloniaObject
+            Func<AvaloniaObject, TValue, TValue>? coerce = null,
+            Action<AvaloniaObject, bool>? notifying = null)
+                where TOwner : AvaloniaObject
         {
             _ = name ?? throw new ArgumentNullException(nameof(name));
 
@@ -279,8 +279,8 @@ public static AttachedProperty<TValue> RegisterAttached<TOwner, THost, TValue>(
             bool inherits = false,
             BindingMode defaultBindingMode = BindingMode.OneWay,
             Func<TValue, bool>? validate = null,
-            Func<IAvaloniaObject, TValue, TValue>? coerce = null)
-                where THost : IAvaloniaObject
+            Func<AvaloniaObject, TValue, TValue>? coerce = null)
+                where THost : AvaloniaObject
         {
             _ = name ?? throw new ArgumentNullException(nameof(name));
 
@@ -316,8 +316,8 @@ public static AttachedProperty<TValue> RegisterAttached<THost, TValue>(
             bool inherits = false,
             BindingMode defaultBindingMode = BindingMode.OneWay,
             Func<TValue, bool>? validate = null,
-            Func<IAvaloniaObject, TValue, TValue>? coerce = null)
-                where THost : IAvaloniaObject
+            Func<AvaloniaObject, TValue, TValue>? coerce = null)
+                where THost : AvaloniaObject
         {
             _ = name ?? throw new ArgumentNullException(nameof(name));
 
@@ -354,7 +354,7 @@ public static DirectProperty<TOwner, TValue> RegisterDirect<TOwner, TValue>(
             TValue unsetValue = default!,
             BindingMode defaultBindingMode = BindingMode.OneWay,
             bool enableDataValidation = false)
-                where TOwner : IAvaloniaObject
+                where TOwner : AvaloniaObject
         {
             _ = name ?? throw new ArgumentNullException(nameof(name));
             _ = getter ?? throw new ArgumentNullException(nameof(getter));
@@ -415,7 +415,7 @@ public override int GetHashCode()
         /// <returns>
         /// The property metadata.
         /// </returns>
-        public AvaloniaPropertyMetadata GetMetadata<T>() where T : IAvaloniaObject
+        public AvaloniaPropertyMetadata GetMetadata<T>() where T : AvaloniaObject
         {
             return GetMetadata(typeof(T));
         }

src/Avalonia.Base/AvaloniaPropertyChangedEventArgs.cs

@@ -9,7 +9,7 @@ namespace Avalonia
     public abstract class AvaloniaPropertyChangedEventArgs : EventArgs
     {
         public AvaloniaPropertyChangedEventArgs(
-            IAvaloniaObject sender,
+            AvaloniaObject sender,
             BindingPriority priority)
         {
             Sender = sender;
@@ -18,7 +18,7 @@ public AvaloniaPropertyChangedEventArgs(
         }
 
         internal AvaloniaPropertyChangedEventArgs(
-            IAvaloniaObject sender,
+            AvaloniaObject sender,
             BindingPriority priority,
             bool isEffectiveValueChange)
         {
@@ -31,7 +31,7 @@ internal AvaloniaPropertyChangedEventArgs(
         /// Gets the <see cref="AvaloniaObject"/> that the property changed on.
         /// </summary>
         /// <value>The sender object.</value>
-        public IAvaloniaObject Sender { get; }
+        public AvaloniaObject Sender { get; }
 
         /// <summary>
         /// Gets the property that changed.