Change order of lines to properly raise events

osu.Framework.Tests/Bindables/BindableBindingTest.cs

@@ -0,0 +1,152 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu-framework/master/LICENCE
+
+using System;
+using NUnit.Framework;
+using osu.Framework.Configuration;
+
+namespace osu.Framework.Tests.Bindables
+{
+    [TestFixture]
+    public class BindableBindingTest
+    {
+        [Test]
+        public void TestPropagation()
+        {
+            Bindable<string> bindable1 = new Bindable<string>("default");
+            Bindable<string> bindable2 = bindable1.GetBoundCopy();
+
+            Assert.AreEqual("default", bindable1.Value);
+            Assert.AreEqual(bindable2.Value, bindable1.Value);
+
+            bindable1.Value = "new value";
+
+            Assert.AreEqual("new value", bindable1.Value);
+            Assert.AreEqual(bindable2.Value, bindable1.Value);
+        }
+
+        [Test]
+        public void TestDisabled()
+        {
+            Bindable<string> bindable1 = new Bindable<string>("default");
+            Bindable<string> bindable2 = bindable1.GetBoundCopy();
+
+            bindable1.Disabled = true;
+
+            Assert.Throws<InvalidOperationException>(() => bindable1.Value = "new value");
+            Assert.Throws<InvalidOperationException>(() => bindable2.Value = "new value");
+
+            bindable1.Disabled = false;
+
+            bindable1.Value = "new value";
+
+            Assert.AreEqual("new value", bindable1.Value);
+            Assert.AreEqual("new value", bindable2.Value);
+
+            bindable2.Value = "new value 2";
+
+            Assert.AreEqual("new value 2", bindable1.Value);
+            Assert.AreEqual("new value 2", bindable2.Value);
+        }
+
+        [Test]
+        public void TestValueChanged()
+        {
+            Bindable<string> bindable1 = new Bindable<string>("default");
+            Bindable<string> bindable2 = bindable1.GetBoundCopy();
+
+            int changed1 = 0, changed2 = 0;
+
+            bindable1.ValueChanged += _ => changed1++;
+            bindable2.ValueChanged += _ => changed2++;
+
+            bindable1.Value = "new value";
+
+            Assert.AreEqual(1, changed1);
+            Assert.AreEqual(1, changed2);
+
+            bindable1.Value = "new value 2";
+
+            Assert.AreEqual(2, changed1);
+            Assert.AreEqual(2, changed2);
+
+            // should not re-fire, as the value hasn't changed.
+            bindable1.Value = "new value 2";
+
+            Assert.AreEqual(2, changed1);
+            Assert.AreEqual(2, changed2);
+        }
+
+        [Test]
+        public void TestValueChangedWithUpstreamRejection()
+        {
+            Bindable<string> bindable1 = new Bindable<string>("won't change");
+            Bindable<string> bindable2 = bindable1.GetBoundCopy();
+
+            int changed1 = 0, changed2 = 0;
+
+            bindable1.ValueChanged += v => changed1++;
+            bindable2.ValueChanged += _ =>
+            {
+                bindable2.Value = "won't change";
+                changed2++;
+            };
+
+            bindable1.Value = "new value";
+
+            Assert.AreEqual("won't change", bindable1.Value);
+            Assert.AreEqual(bindable1.Value, bindable2.Value);
+
+            // bindable1 should only receive the final value changed, skipping the intermediary (overidden) one.
+            Assert.AreEqual(1, changed1);
+            Assert.AreEqual(2, changed2);
+        }
+
+        [Test]
+        public void TestDisabledChanged()
+        {
+            Bindable<string> bindable1 = new Bindable<string>("default");
+            Bindable<string> bindable2 = bindable1.GetBoundCopy();
+
+            bool disabled1 = false, disabled2 = false;
+
+            bindable1.DisabledChanged += v => disabled1 = v;
+            bindable2.DisabledChanged += v => disabled2 = v;
+
+            bindable1.Disabled = true;
+
+            Assert.AreEqual(true, disabled1);
+            Assert.AreEqual(true, disabled2);
+
+            bindable1.Disabled = false;
+
+            Assert.AreEqual(false, disabled1);
+            Assert.AreEqual(false, disabled2);
+        }
+
+        [Test]
+        public void TestDisabledChangedWithUpstreamRejection()
+        {
+            Bindable<string> bindable1 = new Bindable<string>("won't change");
+            Bindable<string> bindable2 = bindable1.GetBoundCopy();
+
+            int changed1 = 0, changed2 = 0;
+
+            bindable1.DisabledChanged += v => changed1++;
+            bindable2.DisabledChanged += _ =>
+            {
+                bindable2.Disabled = false;
+                changed2++;
+            };
+
+            bindable1.Disabled = true;
+
+            Assert.IsFalse(bindable1.Disabled);
+            Assert.IsFalse(bindable2.Disabled);
+
+            // bindable1 should only receive the final disabled changed, skipping the intermediary (overidden) one.
+            Assert.AreEqual(1, changed1);
+            Assert.AreEqual(2, changed2);
+        }
+    }
+}

osu.Framework/Configuration/Bindable.cs

@@ -164,14 +164,20 @@ public virtual void TriggerChange()
 
         protected void TriggerValueChange(bool propagateToBindings = true)
         {
-            ValueChanged?.Invoke(value);
+            // check a bound bindable hasn't changed the value again (it will fire its own event)
+            T beforePropagation = value;
             if (propagateToBindings) Bindings?.ForEachAlive(b => b.Value = value);
+            if (Equals(beforePropagation, Value))
+                ValueChanged?.Invoke(value);
         }
 
         protected void TriggerDisabledChange(bool propagateToBindings = true)
         {
-            DisabledChanged?.Invoke(disabled);
+            // check a bound bindable hasn't changed the value again (it will fire its own event)
+            bool beforePropagation = disabled;
             if (propagateToBindings) Bindings?.ForEachAlive(b => b.Disabled = disabled);
+            if (Equals(beforePropagation, Disabled))
+                DisabledChanged?.Invoke(disabled);
         }
 
         /// <summary>