Binding System refactor

.ncrunch/Avalonia.Tizen.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

.ncrunch/ControlCatalog.Tizen.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

.ncrunch/ControlCatalog.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

.ncrunch/PInvoke.net6.0.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

.ncrunch/PInvoke.netstandard2.0.v3.ncrunchproject

@@ -0,0 +1,5 @@
+<ProjectConfiguration>
+  <Settings>
+    <IgnoreThisComponentCompletely>True</IgnoreThisComponentCompletely>
+  </Settings>
+</ProjectConfiguration>

samples/BindingDemo/MainWindow.xaml

@@ -23,6 +23,7 @@
           <StackPanel Margin="18" Spacing="4" Width="200">
             <TextBlock FontSize="16" Text="Simple Bindings"/>
             <TextBox Watermark="Two Way" UseFloatingWatermark="True" Text="{Binding Path=StringValue}" Name="first"/>
+            <TextBox Watermark="Two Way (LostFocus)" UseFloatingWatermark="True" Text="{Binding Path=StringValue, UpdateSourceTrigger=LostFocus}"/>
             <TextBox Watermark="One Way" UseFloatingWatermark="True" Text="{Binding Path=StringValue, Mode=OneWay}"/>
             <TextBox Watermark="One Time" UseFloatingWatermark="True" Text="{Binding Path=StringValue, Mode=OneTime}"/>
             <!-- Removed due to #2983: reinstate when that's fixed.

src/Avalonia.Base/Animation/AnimatorKeyFrame.cs

@@ -47,11 +47,11 @@ public IDisposable BindSetter(IAnimationSetter setter, Animatable targetControl)
 
             if (value is IBinding binding)
             {
-                return this.Bind(ValueProperty, binding, targetControl);
+                return Bind(ValueProperty, binding, targetControl);
             }
             else
             {
-                return this.Bind(ValueProperty, Observable.SingleValue(value).ToBinding(), targetControl);
+                return Bind(ValueProperty, Observable.SingleValue(value).ToBinding(), targetControl);
             }
         }
 

src/Avalonia.Base/AvaloniaObject.cs

@@ -3,9 +3,11 @@
 using System.ComponentModel;
 using System.Runtime.CompilerServices;
 using Avalonia.Data;
+using Avalonia.Data.Core;
 using Avalonia.Diagnostics;
 using Avalonia.Logging;
 using Avalonia.PropertyStore;
+using Avalonia.Reactive;
 using Avalonia.Threading;
 
 namespace Avalonia
@@ -406,6 +408,19 @@ public void SetCurrentValue<T>(StyledProperty<T> property, T value)
             }
         }
 
+        /// <summary>
+        /// Binds a <see cref="AvaloniaProperty"/> to an <see cref="IBinding"/>.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        /// <param name="binding">The binding.</param>
+        /// <returns>
+        /// The binding expression which represents the binding instance on this object.
+        /// </returns>
+        public BindingExpressionBase Bind(AvaloniaProperty property, IBinding binding)
+        {
+            return Bind(property, binding, null);
+        }
+
         /// <summary>
         /// Binds a <see cref="AvaloniaProperty"/> to an observable.
         /// </summary>
@@ -440,7 +455,21 @@ public IDisposable Bind<T>(
             VerifyAccess();
             ValidatePriority(priority);
 
-            return _values.AddBinding(property, source, priority);
+            if (source is IBinding2 b)
+            {
+                if (b.Instance(this, property, null) is not UntypedBindingExpressionBase expression)
+                    throw new NotSupportedException("Binding returned unsupported IBindingExpression.");
+                if (priority != expression.Priority)
+                    throw new NotSupportedException(
+                        $"The binding priority passed to AvaloniaObject.Bind ('{priority}') " +
+                        "conflicts with the binding priority of the provided binding expression " +
+                        $" ({expression.Priority}').");
+                return GetValueStore().AddBinding(property, expression);
+            }
+            else
+            {
+                return _values.AddBinding(property, source, priority);
+            }
         }
 
         /// <summary>
@@ -512,7 +541,16 @@ public IDisposable Bind<T>(
                 throw new ArgumentException($"The property {property.Name} is readonly.");
             }
 
-            return _values.AddBinding(property, source);
+            if (source is IBinding2 b)
+            {
+                if (b.Instance(this, property, null) is not UntypedBindingExpressionBase expression)
+                    throw new NotSupportedException("Binding returned unsupported IBindingExpression.");
+                return GetValueStore().AddBinding(property, expression);
+            }
+            else
+            {
+                return _values.AddBinding(property, source);
+            }
         }
 
         /// <summary>
@@ -573,6 +611,30 @@ public IDisposable Bind<T>(
         /// <param name="property">The property.</param>
         public void CoerceValue(AvaloniaProperty property) => _values.CoerceValue(property);
 
+        /// <summary>
+        /// Binds a <see cref="AvaloniaProperty"/> to an <see cref="IBinding"/>.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        /// <param name="binding">The binding.</param>
+        /// <param name="anchor">
+        /// An optional anchor from which to locate required context. When binding to objects that
+        /// are not in the logical tree, certain types of binding need an anchor into the tree in 
+        /// order to locate named controls or resources. The <paramref name="anchor"/> parameter 
+        /// can be used to provide this context.
+        /// </param>
+        /// <returns>
+        /// The binding expression which represents the binding instance on this object.
+        /// </returns>
+        internal BindingExpressionBase Bind(AvaloniaProperty property, IBinding binding, object? anchor)
+        {
+            if (binding is not IBinding2 b)
+                throw new NotSupportedException($"Unsupported IBinding implementation '{binding}'.");
+            if (b.Instance(this, property, anchor) is not UntypedBindingExpressionBase expression)
+                throw new NotSupportedException("Binding returned unsupported IBindingExpression.");
+
+            return GetValueStore().AddBinding(property, expression);
+        }
+
         internal void AddInheritanceChild(AvaloniaObject child)
         {
             _inheritanceChildren ??= new List<AvaloniaObject>();
@@ -608,22 +670,6 @@ internal AvaloniaPropertyValue GetDiagnosticInternal(AvaloniaProperty property)
         internal ValueStore GetValueStore() => _values;
         internal IReadOnlyList<AvaloniaObject>? GetInheritanceChildren() => _inheritanceChildren;
 
-        /// <summary>
-        /// Gets a logger to which a binding warning may be written.
-        /// </summary>
-        /// <param name="property">The property that the error occurred on.</param>
-        /// <param name="e">The binding exception, if any.</param>
-        /// <remarks>
-        /// This is overridden in <see cref="Visual"/> to prevent logging binding errors when a
-        /// control is not attached to the visual tree.
-        /// </remarks>
-        internal virtual ParametrizedLogger? GetBindingWarningLogger(
-            AvaloniaProperty property,
-            Exception? e)
-        {
-            return Logger.TryGet(LogEventLevel.Warning, LogArea.Binding);
-        }
-
         /// <summary>
         /// Called to update the validation state for properties for which data validation is
         /// enabled.
@@ -757,8 +803,6 @@ internal void SetDirectValueUnchecked<T>(DirectPropertyBase<T> property, T value
         /// <param name="value">The value.</param>
         internal void SetDirectValueUnchecked<T>(DirectPropertyBase<T> property, BindingValue<T> value)
         {
-            LoggingUtils.LogIfNecessary(this, property, value);
-
             switch (value.Type)
             {
                 case BindingValueType.UnsetValue:

src/Avalonia.Base/AvaloniaObjectExtensions.cs

@@ -1,5 +1,6 @@
 using System;
 using Avalonia.Data;
+using Avalonia.Data.Core;
 using Avalonia.Reactive;
 
 namespace Avalonia
@@ -233,9 +234,10 @@ public static IDisposable Bind<T>(
         /// An optional anchor from which to locate required context. When binding to objects that
         /// are not in the logical tree, certain types of binding need an anchor into the tree in 
         /// order to locate named controls or resources. The <paramref name="anchor"/> parameter 
-        /// can be used to provice this context.
+        /// can be used to provide this context.
         /// </param>
         /// <returns>An <see cref="IDisposable"/> which can be used to cancel the binding.</returns>
+        [Obsolete("Use AvaloniaObject.Bind(AvaloniaProperty, IBinding")]
         public static IDisposable Bind(
             this AvaloniaObject target,
             AvaloniaProperty property,
@@ -246,20 +248,7 @@ public static IDisposable Bind(
             property = property ?? throw new ArgumentNullException(nameof(property));
             binding = binding ?? throw new ArgumentNullException(nameof(binding));
 
-            var result = binding.Initiate(
-                target,
-                property,
-                anchor,
-                property.GetMetadata(target.GetType()).EnableDataValidation ?? false);
-
-            if (result != null)
-            {
-                return BindingOperations.Apply(target, property, result, anchor);
-            }
-            else
-            {
-                return Disposable.Empty;
-            }
+            return target.Bind(property, binding);
         }
 
         /// <summary>
@@ -367,7 +356,7 @@ public static IDisposable AddClassHandler<TTarget, TValue>(
             return observable.Subscribe(new ClassHandlerObserver<TTarget, TValue>(action));
         }
 
-        private class BindingAdaptor : IBinding
+        private class BindingAdaptor : IBinding2
         {
             private readonly IObservable<object?> _source;
 
@@ -382,7 +371,13 @@ public BindingAdaptor(IObservable<object?> source)
                 object? anchor = null,
                 bool enableDataValidation = false)
             {
-                return InstancedBinding.OneWay(_source);
+                var expression = new UntypedObservableBindingExpression(_source, BindingPriority.LocalValue);
+                return new InstancedBinding(expression, BindingMode.OneWay, BindingPriority.LocalValue);
+            }
+
+            BindingExpressionBase IBinding2.Instance(AvaloniaObject target, AvaloniaProperty property, object? anchor)
+            {
+                return new UntypedObservableBindingExpression(_source, BindingPriority.LocalValue);
             }
         }
 

src/Avalonia.Base/AvaloniaProperty.cs

@@ -542,6 +542,14 @@ public override string ToString()
         /// <param name="value">The value.</param>
         internal abstract void RouteSetCurrentValue(AvaloniaObject o, object? value);
 
+        /// <summary>
+        /// Routes an untyped SetDirectValueUnchecked call to a typed call.
+        /// </summary>
+        /// <param name="o">The object instance.</param>
+        /// <param name="value">The value.</param>
+        internal virtual void RouteSetDirectValueUnchecked(AvaloniaObject o, object? value) =>
+            throw new NotSupportedException();
+
         /// <summary>
         /// Routes an untyped Bind call to a typed call.
         /// </summary>

src/Avalonia.Base/ClassBindingManager.cs

@@ -14,7 +14,7 @@ public static IDisposable Bind(StyledElement target, string className, IBinding
         {
             if (!s_RegisteredProperties.TryGetValue(className, out var prop))
                 s_RegisteredProperties[className] = prop = RegisterClassProxyProperty(className);
-            return target.Bind(prop, source, anchor);
+            return target.Bind(prop, source);
         }
 
         [System.Diagnostics.CodeAnalysis.SuppressMessage("AvaloniaProperty", "AVP1001:The same AvaloniaProperty should not be registered twice",

src/Avalonia.Base/Data/BindingChainException.cs

@@ -4,8 +4,8 @@ namespace Avalonia.Data
 {
     /// <summary>
     /// An exception returned through <see cref="BindingNotification"/> signaling that a
-    /// requested binding expression could not be evaluated because of a null in one of the links
-    /// of the binding chain.
+    /// requested binding expression could not be evaluated because of an error in one of
+    /// the links of the binding chain.
     /// </summary>
     public class BindingChainException : Exception
     {
@@ -60,15 +60,15 @@ public override string Message
             {
                 if (Expression != null && ExpressionErrorPoint != null)
                 {
-                    return $"{_message} in expression '{Expression}' at '{ExpressionErrorPoint}'.";
+                    return $"An error occured binding to '{Expression}' at '{ExpressionErrorPoint}': '{_message}'";
                 }
-                else if (ExpressionErrorPoint != null)
+                else if (Expression != null)
                 {
-                    return $"{_message} in expression '{ExpressionErrorPoint}'.";
+                    return $"An error occured binding to '{Expression}': '{_message}'";
                 }
                 else
                 {
-                    return $"{_message} in expression.";
+                    return $"An error occured in a binding: '{_message}'";
                 }
             }
         }

src/Avalonia.Base/Data/BindingExpressionBase.cs

@@ -0,0 +1,55 @@
+using System;
+using Avalonia.PropertyStore;
+using Avalonia.Styling;
+
+namespace Avalonia.Data;
+
+public abstract class BindingExpressionBase : IDisposable, ISetterInstance
+{
+    private protected BindingExpressionBase()
+    {
+    }
+
+    internal BindingMode Mode { get; private protected set; }
+
+    public virtual void Dispose()
+    {
+        GC.SuppressFinalize(this);
+    }
+
+    /// <summary>
+    /// Sends the current binding target value to the binding source property in 
+    /// <see cref="BindingMode.TwoWay"/> or <see cref="BindingMode.OneWayToSource"/> bindings.
+    /// </summary>
+    /// <remarks>
+    /// This method does nothing when the Mode of the binding is not 
+    /// <see cref="BindingMode.TwoWay"/> or <see cref="BindingMode.OneWayToSource"/>.
+    /// 
+    /// If the UpdateSourceTrigger value of your binding is set to
+    /// <see cref="UpdateSourceTrigger.Explicit"/>, you must call the 
+    /// <see cref="UpdateSource"/> method or the changes will not propagate back to the
+    /// source.
+    /// </remarks>
+    public virtual void UpdateSource() { }
+
+    /// <summary>
+    /// Forces a data transfer from the binding source to the binding target.
+    /// </summary>
+    public virtual void UpdateTarget() { }
+
+    /// <summary>
+    /// When overridden in a derived class, attaches the binding expression to a value store but
+    /// does not start it.
+    /// </summary>
+    /// <param name="valueStore">The value store to attach to.</param>
+    /// <param name="frame">The immediate value frame to attach to, if any.</param>
+    /// <param name="target">The target object.</param>
+    /// <param name="targetProperty">The target property.</param>
+    /// <param name="priority">The priority of the binding.</param>
+    internal abstract void Attach(
+        ValueStore valueStore,
+        ImmediateValueFrame? frame,
+        AvaloniaObject target,
+        AvaloniaProperty targetProperty,
+        BindingPriority priority);
+}