restore focus back to previous element on dialog close

Author: ButchersBoy

MaterialDesignThemes.Wpf/DialogHost.cs

@@ -69,7 +69,8 @@ public class DialogHost : ContentControl
         private DialogOpenedEventHandler _attachedDialogOpenedEventHandler;
         private DialogClosingEventHandler _attachedDialogClosingEventHandler;        
         private object _closeDialogExecutionParameter;
-        private IInputElement _restoreFocus;
+        private IInputElement _restoreFocusDialogClose;        
+        private IInputElement _restoreFocusWindowReactivation;
         private Action _currentSnackbarMessageQueueUnPauseAction = null;
         private Action _closeCleanUp = () => { };
 
@@ -237,8 +238,8 @@ public object Identifier
 
         private static void IsOpenPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
         {
-            var dialogHost = (DialogHost)dependencyObject;
-            
+            var dialogHost = (DialogHost)dependencyObject;            
+
             if (dialogHost._popupContentControl != null)
                 ValidationAssist.SetSuppress(dialogHost._popupContentControl, !dialogHost.IsOpen);
             VisualStateManager.GoToState(dialogHost, dialogHost.SelectState(), !TransitionAssist.GetDisableTransitions(dialogHost));
@@ -260,12 +261,15 @@ private static void IsOpenPropertyChangedCallback(DependencyObject dependencyObj
                 dialogHost._session.IsEnded = true;
                 dialogHost._session = null;
                 dialogHost._closeCleanUp();
-                
+                dialogHost.Dispatcher.InvokeAsync(() => dialogHost._restoreFocusDialogClose.Focus(), DispatcherPriority.Input);
+
                 return;
             }
 
             dialogHost._asyncShowWaitHandle.Reset();
             dialogHost._session = new DialogSession(dialogHost);
+            var window = Window.GetWindow(dialogHost);
+            dialogHost._restoreFocusDialogClose = window != null ? FocusManager.GetFocusedElement(window) : null;
 
             //multiple ways of calling back that the dialog has opened:
             // * routed event
@@ -507,7 +511,7 @@ public static DialogClosingEventHandler GetDialogClosingAttached(DependencyObjec
         }        
 
         public static readonly DependencyProperty DialogClosingCallbackProperty = DependencyProperty.Register(
-            nameof(DialogClosingCallback), typeof (DialogClosingEventHandler), typeof (DialogHost), new PropertyMetadata(default(DialogClosingEventHandler)));
+            nameof(DialogClosingCallback), typeof (DialogClosingEventHandler), typeof (DialogHost), new PropertyMetadata(default(DialogClosingEventHandler)));        
 
         /// <summary>
         /// Callback fired when the <see cref="DialogClosing"/> event is fired, allowing the event to be processed from a binding/view model.
@@ -678,16 +682,16 @@ private static void WatchWindowActivation(DialogHost dialogHost)
 
         private void WindowOnDeactivated(object sender, EventArgs eventArgs)
         {            
-            _restoreFocus = _popup != null ? FocusManager.GetFocusedElement((Window)sender) : null;
+            _restoreFocusWindowReactivation = _popup != null ? FocusManager.GetFocusedElement((Window)sender) : null;
         }
 
         private void WindowOnActivated(object sender, EventArgs eventArgs)
         {
-            if (_restoreFocus != null)
+            if (_restoreFocusWindowReactivation != null)
             {
                 Dispatcher.BeginInvoke(new Action(() =>
                 {                    
-                    Keyboard.Focus(_restoreFocus);
+                    Keyboard.Focus(_restoreFocusWindowReactivation);
                 }));
             }
         }

MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.Button.xaml

@@ -60,6 +60,9 @@
                         <Trigger Property="IsMouseOver" Value="true">
                             <Setter TargetName="border" Property="wpf:ShadowAssist.Darken" Value="True" />
                         </Trigger>
+                        <Trigger Property="IsKeyboardFocused" Value="true">
+                            <Setter TargetName="border" Property="wpf:ShadowAssist.Darken" Value="True" />
+                        </Trigger>
                         <Trigger Property="IsEnabled" Value="false">
                             <Setter Property="Opacity" Value="0.23"/>
                         </Trigger>
@@ -205,6 +208,9 @@
                         <Trigger Property="IsMouseOver" Value="True">
                             <Setter TargetName="border" Property="wpf:ShadowAssist.Darken" Value="True" />
                         </Trigger>
+                        <Trigger Property="IsKeyboardFocused" Value="true">
+                            <Setter TargetName="border" Property="wpf:ShadowAssist.Darken" Value="True" />
+                        </Trigger>
                     </ControlTemplate.Triggers>
                 </ControlTemplate>
             </Setter.Value>