Merge pull request #720 from vanderkleij/component-command-binding

Support for the Enabled property of Components in the WinForms command binder

Author: Paul Betts

ReactiveUI.Tests/Winforms/CommandBindingTests.cs

@@ -4,6 +4,7 @@
 using System.Windows.Forms;
 using ReactiveUI.Winforms;
 using Xunit;
+using System.ComponentModel;
 
 namespace ReactiveUI.Tests.Winforms
 {
@@ -25,14 +26,12 @@ public void CommandBinderBindsToButton()
                 commandExecuted = true;
             });
 
-            var disp = fixture.BindCommandToObject(cmd, input, Observable.Return((object)5));
-
-            input.PerformClick();
-
-            Assert.True(commandExecuted);
-            Assert.NotNull(ea);
-            disp.Dispose();
+            using (var disp = fixture.BindCommandToObject(cmd, input, Observable.Return((object)5))) {
+                input.PerformClick();
 
+                Assert.True(commandExecuted);
+                Assert.NotNull(ea);
+            }
         }
 
         [Fact]
@@ -51,14 +50,36 @@ public void CommandBinderBindsToCustomControl()
                 commandExecuted = true;
             });
 
-            var disp = fixture.BindCommandToObject(cmd, input, Observable.Return((object)5));
+            using (var disp = fixture.BindCommandToObject(cmd, input, Observable.Return((object)5))) {
+                input.PerformClick();
 
-            input.PerformClick();
+                Assert.True(commandExecuted);
+                Assert.NotNull(ea);
+            }
+        }
 
-            Assert.True(commandExecuted);
-            Assert.NotNull(ea);
-            disp.Dispose();
+        [Fact]
+        public void CommandBinderBindsToCustomComponent()
+        {
+            var fixture = new CreatesWinformsCommandBinding();
+            var cmd = ReactiveCommand.Create();
+            var input = new CustomClickableComponent { };
 
+            Assert.True(fixture.GetAffinityForObject(input.GetType(), true) > 0);
+            Assert.True(fixture.GetAffinityForObject(input.GetType(), false) > 0);
+            bool commandExecuted = false;
+            object ea = null;
+            cmd.Subscribe(o => {
+                ea = o;
+                commandExecuted = true;
+            });
+
+            using (var disp = fixture.BindCommandToObject(cmd, input, Observable.Return((object)5))) {
+                input.PerformClick();
+
+                Assert.True(commandExecuted);
+                Assert.NotNull(ea);
+            }
         }
 
         [Fact]
@@ -73,16 +94,44 @@ public void CommandBinderAffectsEnabledState()
 
             using (var disp = fixture.BindCommandToObject(cmd, input, Observable.Return((object)5))) {
                 canExecute.OnNext(true);
-
                 Assert.True(input.Enabled);
 
                 canExecute.OnNext(false);
+                Assert.False(input.Enabled);
+            }
+        }
 
+        [Fact]
+        public void CommandBinderAffectsEnabledStateForComponents()
+        {
+            var fixture = new CreatesWinformsCommandBinding();
+            var canExecute = new Subject<bool>();
+            canExecute.OnNext(true);
+
+            var cmd = ReactiveCommand.Create(canExecute);
+            var input = new ToolStripButton { }; // ToolStripButton is a Component, not a Control
+
+            using (var disp = fixture.BindCommandToObject(cmd, input, Observable.Return((object)5))) {
+                canExecute.OnNext(true);
+                Assert.True(input.Enabled);
+
+                canExecute.OnNext(false);
                 Assert.False(input.Enabled);
             }
         }
     }
 
+    public class CustomClickableComponent : Component
+    {
+        public event EventHandler Click;
+
+        public void PerformClick()
+        {
+            if (Click != null)
+                Click(this, EventArgs.Empty);
+        }
+    }
+
     public class CustomClickableControl : Control
     {
         public void PerformClick()
@@ -99,7 +148,6 @@ public void RaiseMouseUpEvent(System.Windows.Forms.MouseEventArgs args)
         {
             this.OnMouseUp(args);
         }
-
     }
 
     public class CommandBindingImplementationTests

ReactiveUI.Winforms/Winforms/CreatesCommandBinding.cs

@@ -8,6 +8,7 @@
 using System.Windows.Input;
 using ReactiveUI;
 using System.Reflection;
+using System.ComponentModel;
 
 namespace ReactiveUI.Winforms
 {
@@ -23,8 +24,6 @@ public class CreatesWinformsCommandBinding : ICreatesCommandBinding
             Tuple.Create("MouseUp", typeof (MouseEventArgs)),
         };
 
-        static readonly PropertyInfo enabledProperty = typeof(Control).GetRuntimeProperty("Enabled");
-
         public int GetAffinityForObject(Type type, bool hasEventTarget)
         {
             bool isWinformControl = typeof(Control).IsAssignableFrom(type);
@@ -33,7 +32,7 @@ public int GetAffinityForObject(Type type, bool hasEventTarget)
 
             if (hasEventTarget) return 6;
 
-            return defaultEventsToBind.Any(x =>{
+            return defaultEventsToBind.Any(x => {
                 var ei = type.GetEvent(x.Item1, BindingFlags.Public | BindingFlags.FlattenHierarchy | BindingFlags.Instance);
                 return ei != null;
             }) ? 4 : 0;
@@ -76,18 +75,27 @@ public IDisposable BindCommandToObject<TEventArgs>(ICommand command, object targ
                     command.Execute(useEventArgsInstead ? ea : latestParameter);
                 }
             }));
-             
-            //only controls have Enabled           
-            if (typeof(Control).IsAssignableFrom(target.GetType())) {
-                object latestParam = null;
-                commandParameter.Subscribe(x => latestParam = x);
-
-                ret.Add(Observable.FromEventPattern<EventHandler, EventArgs>(x => command.CanExecuteChanged += x, x => command.CanExecuteChanged -= x)
-                    .Select(_ => command.CanExecute(latestParam))
-                    .StartWith(command.CanExecute(latestParam))
-                    .Subscribe(x => {
-                        enabledProperty.SetValue(target, x, null);
-                    }));
+
+            Type targetType = target.GetType();
+
+            // We initially only accepted Controls here, but this is too restrictive:
+            // there are a number of Components that can trigger Commands and also
+            // have an Enabled property, just like Controls.
+            // For example: System.Windows.Forms.ToolStripButton.
+            if (typeof(Component).IsAssignableFrom(targetType)) {
+                PropertyInfo enabledProperty = targetType.GetRuntimeProperty("Enabled");
+
+                if (enabledProperty != null) {
+                    object latestParam = null;
+                    commandParameter.Subscribe(x => latestParam = x);
+
+                    ret.Add(Observable.FromEventPattern<EventHandler, EventArgs>(x => command.CanExecuteChanged += x, x => command.CanExecuteChanged -= x)
+                        .Select(_ => command.CanExecute(latestParam))
+                        .StartWith(command.CanExecute(latestParam))
+                        .Subscribe(x => {
+                            enabledProperty.SetValue(target, x, null);
+                        }));
+                }
             }
 
             return ret;