fixed propertychanged with empty string

PrismLibrary · Oct 1, 2020 · ad6a286 · ad6a286
1 parent 2617907
commit ad6a286
Show file tree

Hide file tree

Showing 2 changed files with 31 additions and 6 deletions.
diff --git a/src/Prism.Core/Commands/PropertyObserverNode.cs b/src/Prism.Core/Commands/PropertyObserverNode.cs
@@ -57,10 +57,7 @@ private void UnsubscribeListener()
 
         private void OnPropertyChanged(object sender, PropertyChangedEventArgs e)
         {
-            // Invoke action when e.PropertyName == null in order to satisfy:
-            //  - DelegateCommandFixture.GenericDelegateCommandObservingPropertyShouldRaiseOnEmptyPropertyName
-            //  - DelegateCommandFixture.NonGenericDelegateCommandObservingPropertyShouldRaiseOnEmptyPropertyName
-            if (e?.PropertyName == PropertyInfo.Name || e?.PropertyName == null)
+            if (e?.PropertyName == PropertyInfo.Name || string.IsNullOrEmpty(e?.PropertyName))
             {
                 _action?.Invoke();
             }

diff --git a/tests/Prism.Core.Tests/Commands/DelegateCommandFixture.cs b/tests/Prism.Core.Tests/Commands/DelegateCommandFixture.cs
@@ -366,7 +366,7 @@ public void NonGenericDelegateCommandShouldNotObserveDuplicateProperties()
         }
 
         [Fact]
-        public void NonGenericDelegateCommandObservingPropertyShouldRaiseOnEmptyPropertyName()
+        public void NonGenericDelegateCommandObservingPropertyShouldRaiseOnNullPropertyName()
         {
             bool canExecuteChangedRaised = false;
 
@@ -379,6 +379,20 @@ public void NonGenericDelegateCommandObservingPropertyShouldRaiseOnEmptyProperty
             Assert.True(canExecuteChangedRaised);
         }
 
+        [Fact]
+        public void NonGenericDelegateCommandObservingPropertyShouldRaiseOnEmptyPropertyName()
+        {
+            bool canExecuteChangedRaised = false;
+
+            var command = new DelegateCommand(() => { }).ObservesProperty(() => IntProperty);
+
+            command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
+
+            RaisePropertyChanged(string.Empty);
+
+            Assert.True(canExecuteChangedRaised);
+        }
+
         [Fact]
         public void NonGenericDelegateCommandShouldObserveOneComplexProperty()
         {
@@ -647,7 +661,7 @@ public void GenericDelegateCommandShouldNotObserveDuplicateProperties()
         }
 
         [Fact]
-        public void GenericDelegateCommandObservingPropertyShouldRaiseOnEmptyPropertyName()
+        public void GenericDelegateCommandObservingPropertyShouldRaiseOnNullPropertyName()
         {
             bool canExecuteChangedRaised = false;
 
@@ -660,6 +674,20 @@ public void GenericDelegateCommandObservingPropertyShouldRaiseOnEmptyPropertyNam
             Assert.True(canExecuteChangedRaised);
         }
 
+        [Fact]
+        public void GenericDelegateCommandObservingPropertyShouldRaiseOnEmptyPropertyName()
+        {
+            bool canExecuteChangedRaised = false;
+
+            var command = new DelegateCommand<object>((o) => { }).ObservesProperty(() => IntProperty);
+
+            command.CanExecuteChanged += delegate { canExecuteChangedRaised = true; };
+
+            RaisePropertyChanged(string.Empty);
+
+            Assert.True(canExecuteChangedRaised);
+        }
+
         [Fact]
         public void GenericDelegateCommandNotObservingPropertiesShouldNotRaiseOnEmptyPropertyName()
         {