Revert "Add ObservesProperty overload on DelegateCommand and DelegateCommand Of T that works for complex property. It takes the complex object to subscribe PropertyChanged listener as first parameter and a lambda with what property to observe as second parameter."

This reverts commit 8afcf605ecec7a502500035a71160d1eeaa3d0f1.

5 files changed, 23 insertions, 202 deletions

diff --git a/Source/Prism.Tests/Commands/DelegateCommandFixture.cs b/Source/Prism.Tests/Commands/DelegateCommandFixture.cs
index adecfec..c70b2c4 100644
--- a/Source/Prism.Tests/Commands/DelegateCommandFixture.cs
+++ b/Source/Prism.Tests/Commands/DelegateCommandFixture.cs
@@ -374,7 +374,7 @@ namespace Prism.Tests.Commands
 
             command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
 
-            RaisePropertyChanged(null);
+			RaisePropertyChanged(null);
 
             Assert.True(canExecuteChangedRaised);
         }
@@ -388,56 +388,12 @@ namespace Prism.Tests.Commands
 
             command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
 
-            RaisePropertyChanged(null);
+			RaisePropertyChanged(null);
 
             Assert.False(canExecuteChangedRaised);
         }
 
         [Fact]
-        public void NonGenericDelegateCommandShouldObserveOneComplexProperty()
-        {
-            bool canExecuteChangedRaised = false;
-
-            var command = new DelegateCommand(() => { }).ObservesProperty(ComplexProperty, p => p.IntProperty);
-
-            command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
-
-            ComplexProperty.IntProperty = 10;
-
-            Assert.True(canExecuteChangedRaised);
-        }
-
-        [Fact]
-        public void NonGenericDelegateCommandShouldObserveMultipleComplexProperties()
-        {
-            bool canExecuteChangedRaised = false;
-
-            var command = new DelegateCommand(() => { }).ObservesProperty(ComplexProperty, p => p.IntProperty)
-                .ObservesProperty(ComplexProperty, p => p.BoolProperty);
-
-            command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
-
-            ComplexProperty.IntProperty = 10;
-
-            Assert.True(canExecuteChangedRaised);
-
-            canExecuteChangedRaised = false;
-
-            ComplexProperty.BoolProperty = true;
-
-            Assert.True(canExecuteChangedRaised);
-        }
-
-        [Fact]
-        public void NonGenericDelegateCommandShouldNotObserveDuplicateComplexProperties()
-        {
-            Assert.Throws<ArgumentException>(() =>
-            {
-                DelegateCommand command = new DelegateCommand(() => { }).ObservesProperty(ComplexProperty, p => p.IntProperty).ObservesProperty(ComplexProperty, p => p.IntProperty);
-            });
-        }
-
-        [Fact]
         public void GenericDelegateCommandShouldObserveCanExecute()
         {
             bool canExecuteChangedRaised = false;
@@ -576,54 +532,12 @@ namespace Prism.Tests.Commands
 
             command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
 
-            RaisePropertyChanged(null);
+			RaisePropertyChanged(null);
 
             Assert.False(canExecuteChangedRaised);
         }
 
-        [Fact]
-        public void GenericDelegateCommandShouldObserveOneComplexProperty()
-        {
-            bool canExecuteChangedRaised = false;
-
-            var command = new DelegateCommand<object>((o) => { }).ObservesProperty(ComplexProperty, p => p.IntProperty);
-
-            command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
-
-            ComplexProperty.IntProperty = 10;
-
-            Assert.True(canExecuteChangedRaised);
-        }
-
-        [Fact]
-        public void GenericDelegateCommandShouldObserveMultipleComplexProperties()
-        {
-            bool canExecuteChangedRaised = false;
-
-            var command = new DelegateCommand<object>((o) => { }).ObservesProperty(ComplexProperty, p => p.IntProperty)
-                .ObservesProperty(ComplexProperty, p => p.BoolProperty);
-
-            command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
-
-            ComplexProperty.IntProperty = 10;
-
-            Assert.True(canExecuteChangedRaised);
-
-            canExecuteChangedRaised = false;
-
-            ComplexProperty.BoolProperty = true;
 
-            Assert.True(canExecuteChangedRaised);
-        }
-
-        [Fact]
-        public void GenericDelegateCommandShouldNotObserveDuplicateComplexProperties()
-        {
-            Assert.Throws<ArgumentException>(() =>
-            {
-                DelegateCommand<object> command = new DelegateCommand<object>((o) => { }).ObservesProperty(ComplexProperty, p => p.IntProperty).ObservesProperty(ComplexProperty, p => p.IntProperty);
-            });
-        }
 
         private bool _boolProperty;
         public bool BoolProperty
@@ -639,30 +553,6 @@ namespace Prism.Tests.Commands
             set { SetProperty(ref _intProperty, value); }
         }
 
-        public class ComplexType : BindableBase
-        {
-            private bool _boolProperty;
-            public bool BoolProperty
-            {
-                get { return _boolProperty; }
-                set { SetProperty(ref _boolProperty, value); }
-            }
-
-            private int _intProperty;
-            public int IntProperty
-            {
-                get { return _intProperty; }
-                set { SetProperty(ref _intProperty, value); }
-            }
-        }
-
-        private ComplexType _complexProperty = new ComplexType();
-        public ComplexType ComplexProperty
-        {
-            get { return _complexProperty; }
-            set { SetProperty(ref _complexProperty, value); }
-        }
-
         class CanExecutChangeHandler
         {
             public bool CanExeucteChangedHandlerCalled;
diff --git a/Source/Prism/Commands/DelegateCommand.cs b/Source/Prism/Commands/DelegateCommand.cs
index d8bb1b0..6111615 100644
--- a/Source/Prism/Commands/DelegateCommand.cs
+++ b/Source/Prism/Commands/DelegateCommand.cs
@@ -80,20 +80,6 @@ namespace Prism.Commands
         }
 
         /// <summary>
-        /// Observes a property that implements INotifyPropertyChanged, and automatically calls DelegateCommandBase.RaiseCanExecuteChanged on property changed notifications.
-        /// </summary>
-        /// <typeparam name="T">The object type containing the property specified in the expression.</typeparam>
-        /// <typeparam name="TProp">The property type specified in the expression.</typeparam>
-        /// <param name="target">The object containing the property to observe</param>
-        /// <param name="propertyExpression">The property expression. Example: ObservesProperty(Person, p => p.FirstName).</param>
-        /// <returns>The current instance of DelegateCommand</returns>
-        public DelegateCommand ObservesProperty<T, TProp>(T target, Expression<Func<T, TProp>> propertyExpression)
-        {
-            ObservesPropertyInternal(target, propertyExpression);
-            return this;
-        }
-
-        /// <summary>
         /// Observes a property that is used to determine if this command can execute, and if it implements INotifyPropertyChanged it will automatically call DelegateCommandBase.RaiseCanExecuteChanged on property changed notifications.
         /// </summary>
         /// <param name="canExecuteExpression">The property expression. Example: ObservesCanExecute(() => PropertyName).</param>
diff --git a/Source/Prism/Commands/DelegateCommandBase.cs b/Source/Prism/Commands/DelegateCommandBase.cs
index d9c1a38..aea000b 100644
--- a/Source/Prism/Commands/DelegateCommandBase.cs
+++ b/Source/Prism/Commands/DelegateCommandBase.cs
@@ -18,8 +18,8 @@ namespace Prism.Commands
 
         private SynchronizationContext _synchronizationContext;
 
-        private readonly HashSet<Tuple<object, string>> _propertiesToObserve = new HashSet<Tuple<object, string>>();
-        private readonly HashSet<INotifyPropertyChanged> _inpc = new HashSet<INotifyPropertyChanged>();
+        readonly HashSet<string> _propertiesToObserve = new HashSet<string>();
+        private INotifyPropertyChanged _inpc;
 
 
         /// <summary>
@@ -85,58 +85,38 @@ namespace Prism.Commands
         /// <param name="propertyExpression">The property expression. Example: ObservesProperty(() => PropertyName).</param>
         protected internal void ObservesPropertyInternal<T>(Expression<Func<T>> propertyExpression)
         {
-            var constantExpression = (propertyExpression?.Body as MemberExpression)?.Expression as ConstantExpression;
-            var objectToObserve = constantExpression?.Value;
-            ObservesPropertyInternal(objectToObserve, PropertySupport.ExtractPropertyName(propertyExpression));
+            AddPropertyToObserve(PropertySupport.ExtractPropertyName(propertyExpression));
+            HookInpc(propertyExpression.Body as MemberExpression);
         }
 
-        protected internal void ObservesPropertyInternal<T, TProp>(T target, Expression<Func<T, TProp>> propertyExpression)
+        protected void HookInpc(MemberExpression expression)
         {
-            ObservesPropertyInternal(target, PropertySupport.ExtractPropertyName(propertyExpression));
-        }
-
-        private void ObservesPropertyInternal(object target, string propertyName)
-        {
-            AddPropertyToObserve(target, propertyName);
-            HookInpc(target);
-        }
-
-        protected void HookInpc(object target)
-        {
-            if (target == null)
-                throw new ArgumentNullException(nameof(target));
-
-            var notifyPropertyChangedObject = target as INotifyPropertyChanged;
+            if (expression == null)
+                return;
 
-            if (notifyPropertyChangedObject == null)
-                throw new InvalidOperationException(string.Format("{0} object must implement INotifyPropertyChanged.", nameof(target)));
-
-            if (!_inpc.Contains(notifyPropertyChangedObject))
+            if (_inpc == null)
             {
-                notifyPropertyChangedObject.PropertyChanged += Inpc_PropertyChanged;
-                _inpc.Add(notifyPropertyChangedObject);
+                var constantExpression = expression.Expression as ConstantExpression;
+                if (constantExpression != null)
+                {
+                    _inpc = constantExpression.Value as INotifyPropertyChanged;
+                    if (_inpc != null)
+                        _inpc.PropertyChanged += Inpc_PropertyChanged;
+                }
             }
         }
 
-        protected void AddPropertyToObserve(object target, string property)
+        protected void AddPropertyToObserve(string property)
         {
-            if (target == null)
-                throw new ArgumentNullException(nameof(target));
-
-            if (string.IsNullOrEmpty(property))
-                throw new ArgumentNullException(nameof(property));
-
-            var propertyToObserve = new Tuple<object, string>(target, property);
-
-            if (_propertiesToObserve.Contains(propertyToObserve))
-                throw new ArgumentException(String.Format("{0} of {1} is already being observed.", property, target.GetType().Name));
+            if (_propertiesToObserve.Contains(property))
+                throw new ArgumentException(String.Format("{0} is already being observed.", property));
 
-            _propertiesToObserve.Add(propertyToObserve);
+            _propertiesToObserve.Add(property);
         }
 
         void Inpc_PropertyChanged(object sender, PropertyChangedEventArgs e)
         {
-            if (_propertiesToObserve.Contains(new Tuple<object, string>(sender, e.PropertyName)) || (string.IsNullOrEmpty(e.PropertyName) && _propertiesToObserve.Count > 0))
+            if (_propertiesToObserve.Contains(e.PropertyName) || (string.IsNullOrEmpty(e.PropertyName) && _propertiesToObserve.Count > 0))
             {
                 RaiseCanExecuteChanged();
             }
diff --git a/Source/Prism/Commands/DelegateCommand{T}.cs b/Source/Prism/Commands/DelegateCommand{T}.cs
index cebfb66..085e3b1 100644
--- a/Source/Prism/Commands/DelegateCommand{T}.cs
+++ b/Source/Prism/Commands/DelegateCommand{T}.cs
@@ -116,20 +116,6 @@ namespace Prism.Commands
         }
 
         /// <summary>
-        /// Observes a property that implements INotifyPropertyChanged, and automatically calls DelegateCommandBase.RaiseCanExecuteChanged on property changed notifications.
-        /// </summary>
-        /// <typeparam name="TType">The object type containing the property specified in the expression.</typeparam>
-        /// <typeparam name="TProp">The property type specified in the expression.</typeparam>
-        /// <param name="target">The object containing the property to observe</param>
-        /// <param name="propertyExpression">The property expression. Example: ObservesProperty(Person, p => p.FirstName).</param>
-        /// <returns>The current instance of DelegateCommand</returns>
-        public DelegateCommand<T> ObservesProperty<TType, TProp>(TType target, Expression<Func<TType, TProp>> propertyExpression)
-        {
-            ObservesPropertyInternal(target, propertyExpression);
-            return this;
-        }
-
-        /// <summary>
         /// Observes a property that is used to determine if this command can execute, and if it implements INotifyPropertyChanged it will automatically call DelegateCommandBase.RaiseCanExecuteChanged on property changed notifications.
         /// </summary>
         /// <param name="canExecuteExpression">The property expression. Example: ObservesCanExecute(() => PropertyName).</param>
diff --git a/Source/Prism/Mvvm/PropertySupport.cs b/Source/Prism/Mvvm/PropertySupport.cs
index 133e5ca..6f26a68 100644
--- a/Source/Prism/Mvvm/PropertySupport.cs
+++ b/Source/Prism/Mvvm/PropertySupport.cs
@@ -33,27 +33,6 @@ namespace Prism.Mvvm
         }
 
         /// <summary>
-        /// Extracts the property name from a property expression.
-        /// </summary>
-        /// <typeparam name="T">The object type containing the property specified in the expression.</typeparam>
-        /// <typeparam name="TProp">The property type specified in the expression.</typeparam>
-        /// <param name="propertyExpression">The property expression (e.g. p => p.PropertyName)</param>
-        /// <returns>The name of the property.</returns>
-        /// <exception cref="ArgumentNullException">Thrown if the <paramref name="propertyExpression"/> is null.</exception>
-        /// <exception cref="ArgumentException">Thrown when the expression is:<br/>
-        ///     Not a <see cref="MemberExpression"/><br/>
-        ///     The <see cref="MemberExpression"/> does not represent a property.<br/>
-        ///     Or, the property is static.
-        /// </exception>
-        public static string ExtractPropertyName<T, TProp>(Expression<Func<T, TProp>> propertyExpression)
-        {
-            if (propertyExpression == null)
-                throw new ArgumentNullException(nameof(propertyExpression));
-
-            return ExtractPropertyNameFromLambda(propertyExpression);
-        }
-
-        /// <summary>
         /// Extracts the property name from a LambdaExpression.
         /// </summary>
         /// <param name="expression">The LambdaExpression</param>