Make ExpressionObserver accept a priority for sets.

This makes auto-expanding the treeview in DevTools work again.

src/Markup/Perspex.Markup.Xaml/Data/Binding.cs

@@ -107,7 +107,8 @@ namespace Perspex.Markup.Xaml.Data
                 targetProperty?.PropertyType ?? typeof(object),
                 Converter ?? DefaultValueConverter.Instance,
                 ConverterParameter,
-                FallbackValue);
+                FallbackValue,
+                Priority);
 
             return new InstancedBinding(subject, Mode, Priority);
         }

src/Markup/Perspex.Markup/Data/ExpressionNode.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Reactive.Subjects;
+using Perspex.Data;
 
 namespace Perspex.Markup.Data
 {
@@ -76,9 +77,9 @@ namespace Perspex.Markup.Data
             }
         }
 
-        public virtual bool SetValue(object value)
+        public virtual bool SetValue(object value, BindingPriority priority)
         {
-            return Next?.SetValue(value) ?? false;
+            return Next?.SetValue(value, priority) ?? false;
         }
 
         public virtual IDisposable Subscribe(IObserver<object> observer)

src/Markup/Perspex.Markup/Data/ExpressionObserver.cs

@@ -7,6 +7,7 @@ using System.Reactive;
 using System.Reactive.Disposables;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
+using Perspex.Data;
 using Perspex.Markup.Data.Plugins;
 
 namespace Perspex.Markup.Data
@@ -105,11 +106,12 @@ namespace Perspex.Markup.Data
         /// Attempts to set the value of a property expression.
         /// </summary>
         /// <param name="value">The value to set.</param>
+        /// <param name="priority">The binding priority to use.</param>
         /// <returns>
         /// True if the value could be set; false if the expression does not evaluate to a 
         /// property.
         /// </returns>
-        public bool SetValue(object value)
+        public bool SetValue(object value, BindingPriority priority = BindingPriority.LocalValue)
         {
             IncrementCount();
 
@@ -120,7 +122,7 @@ namespace Perspex.Markup.Data
 
             try
             {
-                return _node?.SetValue(value) ?? false;
+                return _node?.SetValue(value, priority) ?? false;
             }
             finally
             {

src/Markup/Perspex.Markup/Data/ExpressionSubject.cs

@@ -5,6 +5,7 @@ using System;
 using System.Globalization;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
+using Perspex.Data;
 using Perspex.Utilities;
 
 namespace Perspex.Markup.Data
@@ -18,6 +19,7 @@ namespace Perspex.Markup.Data
         private readonly ExpressionObserver _inner;
         private readonly Type _targetType;
         private readonly object _fallbackValue;
+        private readonly BindingPriority _priority;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="ExpressionObserver"/> class.
@@ -41,12 +43,14 @@ namespace Perspex.Markup.Data
         /// <param name="fallbackValue">
         /// The value to use when the binding is unable to produce a value.
         /// </param>
+        /// <param name="priority">The binding priority.</param>
         public ExpressionSubject(
             ExpressionObserver inner, 
             Type targetType, 
             IValueConverter converter,
             object converterParameter = null,
-            object fallbackValue = null)
+            object fallbackValue = null,
+            BindingPriority priority = BindingPriority.LocalValue)
         {
             Contract.Requires<ArgumentNullException>(inner != null);
             Contract.Requires<ArgumentNullException>(targetType != null);
@@ -57,6 +61,7 @@ namespace Perspex.Markup.Data
             Converter = converter;
             ConverterParameter = converterParameter;
             _fallbackValue = fallbackValue;
+            _priority = priority;
         }
 
         /// <summary>
@@ -100,7 +105,7 @@ namespace Perspex.Markup.Data
                     converted = TypeUtilities.Default(type);
                 }
 
-                _inner.SetValue(converted);
+                _inner.SetValue(converted, _priority);
             }
         }
 

src/Markup/Perspex.Markup/Data/LogicalNotNode.cs

@@ -4,12 +4,13 @@
 using System;
 using System.Globalization;
 using System.Reactive.Linq;
+using Perspex.Data;
 
 namespace Perspex.Markup.Data
 {
     internal class LogicalNotNode : ExpressionNode
     {
-        public override bool SetValue(object value)
+        public override bool SetValue(object value, BindingPriority priority)
         {
             return false;
         }

src/Markup/Perspex.Markup/Data/Plugins/IPropertyAccessor.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using Perspex.Data;
 
 namespace Perspex.Markup.Data.Plugins
 {
@@ -27,9 +28,12 @@ namespace Perspex.Markup.Data.Plugins
         /// <param name="value">
         /// The value to set. Guaranteed to be of a valid type for the property.
         /// </param>
+        /// <param name="priority">
+        /// The priority with which to set the value.
+        /// </param>
         /// <returns>
         /// True if the property was set; false if the property could not be set.
         /// </returns>
-        bool SetValue(object value);
+        bool SetValue(object value, BindingPriority priority);
     }
 }

src/Markup/Perspex.Markup/Data/Plugins/InpcPropertyAccessorPlugin.cs

@@ -6,6 +6,7 @@ using System.ComponentModel;
 using System.Linq;
 using System.Reactive.Linq;
 using System.Reflection;
+using Perspex.Data;
 using Perspex.Utilities;
 
 namespace Perspex.Markup.Data.Plugins
@@ -106,7 +107,7 @@ namespace Perspex.Markup.Data.Plugins
                 }
             }
 
-            public bool SetValue(object value)
+            public bool SetValue(object value, BindingPriority priority)
             {
                 if (_property.CanWrite)
                 {

src/Markup/Perspex.Markup/Data/Plugins/PerspexPropertyAccessorPlugin.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Reactive.Linq;
+using Perspex.Data;
 
 namespace Perspex.Markup.Data.Plugins
 {
@@ -95,11 +96,11 @@ namespace Perspex.Markup.Data.Plugins
                 _subscription = null;
             }
 
-            public bool SetValue(object value)
+            public bool SetValue(object value, BindingPriority priority)
             {
                 if (!_property.IsReadOnly)
                 {
-                    Instance.SetValue(_property, value);
+                    Instance.SetValue(_property, value, priority);
                     return true;
                 }
 

src/Markup/Perspex.Markup/Data/PropertyAccessorNode.cs

@@ -8,6 +8,7 @@ using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Input;
+using Perspex.Data;
 using Perspex.Markup.Data.Plugins;
 
 namespace Perspex.Markup.Data
@@ -26,17 +27,17 @@ namespace Perspex.Markup.Data
 
         public Type PropertyType => _accessor?.PropertyType;
 
-        public override bool SetValue(object value)
+        public override bool SetValue(object value, BindingPriority priority)
         {
             if (Next != null)
             {
-                return Next.SetValue(value);
+                return Next.SetValue(value, priority);
             }
             else
             {
                 if (_accessor != null)
                 {
-                    return _accessor.SetValue(value);
+                    return _accessor.SetValue(value, priority);
                 }
 
                 return false;