From eb2da81b9d0ce0c28ea7c274204e9c25c2b6a5bf Mon Sep 17 00:00:00 2001
From: Antony Male <antony.male@gmail.com>
Date: Sun, 30 Sep 2018 18:39:07 +0100
Subject: [PATCH] Deprecate BindWeak

Weak event subscriptions are basically impossible to get right, if
you allow anonymous delegates.

Fixes #38
---
 Stylet/PropertyChangedExtensions.cs           |  3 +-
 .../PropertyChangedExtensionsTests.cs         | 97 -------------------
 2 files changed, 2 insertions(+), 98 deletions(-)

diff --git a/Stylet/PropertyChangedExtensions.cs b/Stylet/PropertyChangedExtensions.cs
index 3ba3caa..4a09487 100644
--- a/Stylet/PropertyChangedExtensions.cs
+++ b/Stylet/PropertyChangedExtensions.cs
@@ -155,7 +155,7 @@ namespace Stylet
         }
 
         /// <summary>
-        /// Weakly bind to PropertyChanged events for a particular property on a particular object
+        /// Obsolete: Weakly bind to PropertyChanged events for a particular property on a particular object
         /// </summary>
         /// <example>someObject.Bind(x => x.PropertyNameToBindTo, newValue => /* do something with the new value */)</example>
         /// <typeparam name="TSource">Type of object providing the PropertyChanged event</typeparam>
@@ -164,6 +164,7 @@ namespace Stylet
         /// <param name="targetSelector">MemberExpression selecting the property to observe for changes (e.g x => x.PropertyName)</param>
         /// <param name="handler">Handler called whenever that property changed</param>
         /// <returns>Something which can be used to undo the binding. You can discard it if you want</returns>
+        [Obsolete("Don't use this - use Bind instead and explicitly .Unbind it when appropriate.", error: true)]
         public static IEventBinding BindWeak<TSource, TProperty>(this TSource target, Expression<Func<TSource, TProperty>> targetSelector, EventHandler<PropertyChangedExtendedEventArgs<TProperty>> handler) where TSource : class, INotifyPropertyChanged
         {
             var attribute = handler.Target.GetType().GetCustomAttribute<CompilerGeneratedAttribute>();
diff --git a/StyletUnitTests/PropertyChangedExtensionsTests.cs b/StyletUnitTests/PropertyChangedExtensionsTests.cs
index 4e7a9d8..dfdf0d1 100644
--- a/StyletUnitTests/PropertyChangedExtensionsTests.cs
+++ b/StyletUnitTests/PropertyChangedExtensionsTests.cs
@@ -38,11 +38,6 @@ namespace StyletUnitTests
                 // Must make sure the compiler doesn't generate an inner class for this, otherwise we're not testing the right thing
                 return notifying.Bind(x => x.Foo, (o, e) => this.LastFoo = e.NewValue);
             }
-
-            public IEventBinding BindWeak(NotifyingClass notifying)
-            {
-                return notifying.BindWeak(x => x.Foo, (o, e) => this.LastFoo = e.NewValue);
-            }
         }
 
         private string newVal;
@@ -125,97 +120,5 @@ namespace StyletUnitTests
 
             Assert.AreEqual(null, newVal);
         }
-
-        [Test]
-        public void WeakBindingBinds()
-        {
-            var c1 = new NotifyingClass();
-            c1.BindWeak(x => x.Foo, (o, e) => this.newVal = e.NewValue);
-            c1.Foo = "bar";
-
-            Assert.AreEqual("bar", this.newVal);
-        }
-
-        [Test]
-        public void WeakBindingIgnoresOtherProperties()
-        {
-            var c1 = new NotifyingClass();
-            c1.BindWeak(x => x.Bar, (o, e) => this.newVal = e.NewValue);
-            c1.Foo = "bar";
-
-            Assert.IsNull(this.newVal);
-        }
-
-        [Test]
-        public void WeakBindingListensToEmptyString()
-        {
-            var c1 = new NotifyingClass();
-            c1.Bar = "bar";
-            c1.BindWeak(x => x.Bar, (o, e) => this.newVal = e.NewValue);
-            c1.NotifyAll();
-
-            Assert.AreEqual("bar", this.newVal);
-        }
-
-        [Test]
-        public void WeakBindingDoesNotRetainBindingClass()
-        {
-            var binding = new BindingClass();
-
-            // Means of determining whether the class has been disposed
-            var weakBinding = new WeakReference<BindingClass>(binding);
-
-            var notifying = new NotifyingClass();
-            binding.BindWeak(notifying);
-
-            
-
-            binding = null;
-            GC.Collect();
-            Assert.IsFalse(weakBinding.TryGetTarget(out binding));
-        }
-
-        [Test]
-        public void WeakBindingDoesNotRetainNotifier()
-        {
-            var binding = new BindingClass();
-            var notifying = new NotifyingClass();
-            // Means of determining whether the class has been disposed
-            var weakNotifying = new WeakReference<NotifyingClass>(notifying);
-            // Retain binder, as that shouldn't affect anything
-            var binder = binding.BindWeak(notifying);
-
-            notifying = null;
-            GC.Collect();
-            Assert.IsFalse(weakNotifying.TryGetTarget(out notifying));
-        }
-
-        [Test]
-        public void WeakBindingUnbinds()
-        {
-            var c1 = new NotifyingClass();
-            var binding = c1.BindWeak(x => x.Bar, (o, e) => this.newVal = e.NewValue);
-            binding.Unbind();
-            c1.Bar = "bar";
-
-            Assert.IsNull(this.newVal);
-        }
-        
-        [Test]
-        public void BindWeakPassesSender()
-        {
-            var c1 = new NotifyingClass();
-            c1.BindWeak(x => x.Foo, (o, e) => this.sender = o);
-            c1.Foo = "foo";
-            Assert.AreEqual(c1, this.sender);
-        }
-
-        [Test]
-        public void BindWeakThrowsIfTargetIsCompilerGenerated()
-        {
-            var c1 = new NotifyingClass();
-            string newVal = null;
-            Assert.Throws<InvalidOperationException>(() => c1.BindWeak(x => x.Foo, (o, e) => newVal = e.NewValue));
-        }
     }
 }