Fix dropdown open/close behavior.

Now that new eventing stuff is in place.

Also fix bug with AddClassHandler where it was triyng to call every
object irregardless of whether it was the correct type.

Perspex.Controls/Button.cs

@@ -27,6 +27,7 @@ namespace Perspex.Controls
         static Button()
         {
             FocusableProperty.OverrideDefaultValue(typeof(Button), true);
+            ClickEvent.AddClassHandler<Button>(x => x.OnClick);
         }
 
         public event EventHandler<RoutedEventArgs> Click
@@ -51,7 +52,7 @@ namespace Perspex.Controls
             return base.ArrangeOverride(finalSize);
         }
 
-        protected virtual void OnClick()
+        protected virtual void OnClick(RoutedEventArgs e)
         {
         }
 
@@ -85,8 +86,6 @@ namespace Perspex.Controls
 
         private void RaiseClickEvent()
         {
-            this.OnClick();
-
             RoutedEventArgs click = new RoutedEventArgs
             {
                 RoutedEvent = ClickEvent,

Perspex.Controls/DropDown.cs

@@ -67,7 +67,10 @@ namespace Perspex.Controls
 
         protected override void OnPointerPressed(PointerPressEventArgs e)
         {
-            this.IsDropDownOpen = !this.IsDropDownOpen;
+            if (!this.IsDropDownOpen)
+            {
+                this.IsDropDownOpen = true;
+            }
         }
 
         protected override void OnTemplateApplied()

Perspex.Controls/Popup.cs

@@ -91,9 +91,8 @@ namespace Perspex.Controls
             }
 
             this.popupRoot.SetPosition(this.GetPosition());
-            this.popupRoot.PointerPressed += this.MaybeClose;
             this.topLevel.Deactivated += this.MaybeClose;
-
+            this.popupRoot.AddHandler(PopupRoot.PointerPressedEvent, this.MaybeClose, RoutingStrategies.Bubble, true);
             this.topLevel.AddHandler(TopLevel.PointerPressedEvent, this.MaybeClose, RoutingStrategies.Tunnel);
 
             this.popupRoot.Show();

Perspex.Controls/Primitives/ToggleButton.cs

@@ -7,6 +7,7 @@
 namespace Perspex.Controls.Primitives
 {
     using System;
+    using Perspex.Interactivity;
 
     public class ToggleButton : Button
     {
@@ -28,7 +29,7 @@ namespace Perspex.Controls.Primitives
             set { this.SetValue(IsCheckedProperty, value); }
         }
 
-        protected override void OnClick()
+        protected override void OnClick(RoutedEventArgs e)
         {
             this.Toggle();
         }

Perspex.Interactivity/RoutedEvent.cs

@@ -133,8 +133,21 @@ namespace Perspex.Interactivity
             RoutingStrategies routes = RoutingStrategies.Direct | RoutingStrategies.Bubble) 
             where TTarget : class
         {
-            var adaptor = (EventHandler<RoutedEventArgs>)((s, e) => handler((TTarget)s)((TEventArgs)e));
-            this.AddClassHandler(typeof(TTarget), adaptor, routes);
+            this.AddClassHandler(typeof(TTarget), (s, e) => ClassHandlerAdapter<TTarget>(s, e, handler), routes);
+        }
+
+        private static void ClassHandlerAdapter<TTarget>(
+            object sender, 
+            RoutedEventArgs e, 
+            Func<TTarget, Action<TEventArgs>> handler) where TTarget : class
+        {
+            var target = sender as TTarget;
+            var args = e as TEventArgs;
+
+            if (target != null && args != null)
+            {
+                handler(target)(args);
+            }
         }
     }
 }