add opened/closing events to drawer host #2015 (#2139)

* add opened/closing events to drawer host

* fix issues to comments from reviewer

Co-authored-by: dstreisselberger <[email protected]>

Author: Streissi

MaterialDesignThemes.Wpf.Tests/DrawerHostTests.cs

@@ -0,0 +1,63 @@
+using System;
+using System.ComponentModel;
+using System.Windows;
+using System.Windows.Controls;
+using Xunit;
+
+namespace MaterialDesignThemes.Wpf.Tests
+{
+    public class DrawerHostTests : IDisposable
+    {
+        private readonly DrawerHost _drawerHost;
+
+        public DrawerHostTests()
+        {
+            _drawerHost = new DrawerHost();
+            _drawerHost.ApplyDefaultStyle();
+            _drawerHost.RaiseEvent(new RoutedEventArgs(FrameworkElement.LoadedEvent));
+        }
+
+        public void Dispose()
+        {
+            _drawerHost.RaiseEvent(new RoutedEventArgs(FrameworkElement.UnloadedEvent));
+        }
+
+        [StaFact]
+        [Description("Issue 2015")]
+        public void WhenOpenedDrawerOpenedEventIsRaised()
+        {
+            Dock expectedPosition = Dock.Left;
+            Dock openedPosition = Dock.Top;
+            _drawerHost.DrawerOpened += DrawerOpened;
+            _drawerHost.IsLeftDrawerOpen = true;
+
+            DrawerHost.CloseDrawerCommand.Execute(Dock.Left, _drawerHost);
+
+            Assert.Equal(expectedPosition, openedPosition);
+
+            void DrawerOpened(object sender, DrawerOpenedEventArgs eventArgs)
+            {
+                openedPosition = eventArgs.Dock;
+            }
+        }
+
+        [StaFact]
+        [Description("Issue 2015")]
+        public void WhenClosingDrawerClosingEventIsRaised()
+        {
+            Dock expectedPosition = Dock.Left;
+            Dock closedPosition = Dock.Top;
+            _drawerHost.DrawerClosing += DrawerClosing;
+            _drawerHost.IsLeftDrawerOpen = true;
+
+            DrawerHost.CloseDrawerCommand.Execute(Dock.Left, _drawerHost);
+
+            Assert.Equal(expectedPosition, closedPosition);
+
+            void DrawerClosing(object sender, DrawerClosingEventArgs eventArgs)
+            {
+                closedPosition = eventArgs.Dock;
+            }
+        }
+    }
+}

MaterialDesignThemes.Wpf/DrawerClosingEventArgs.cs

@@ -0,0 +1,31 @@
+using System.Windows;
+using System.Windows.Controls;
+
+namespace MaterialDesignThemes.Wpf
+{
+    public class DrawerClosingEventArgs : RoutedEventArgs
+    {
+        public DrawerClosingEventArgs(Dock dock, RoutedEvent routedEvent) : base(routedEvent)
+        {
+            Dock = dock;
+        }
+
+        /// <summary>
+        /// Cancel the close.
+        /// </summary>
+        public void Cancel()
+        {
+            IsCancelled = true;
+        }
+
+        /// <summary>
+        /// Indicates if the close has already been cancelled.
+        /// </summary>
+        public bool IsCancelled { get; private set; }
+
+        /// <summary>
+        /// Allows interation with the current dialog session.
+        /// </summary>
+        public Dock Dock { get; }
+    }
+}

MaterialDesignThemes.Wpf/DrawerHost.cs

@@ -1,11 +1,10 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
 using System.Windows.Media;
-using MaterialDesignThemes.Wpf.Transitions;
-using System.Collections.Generic;
 
 namespace MaterialDesignThemes.Wpf
 {
@@ -135,7 +134,7 @@ public Brush TopDrawerBackground
         }
 
         public static readonly DependencyProperty IsTopDrawerOpenProperty = DependencyProperty.Register(
-            nameof(IsTopDrawerOpen), typeof(bool), typeof(DrawerHost), new FrameworkPropertyMetadata(default(bool), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsDrawerOpenPropertyChangedCallback));
+            nameof(IsTopDrawerOpen), typeof(bool), typeof(DrawerHost), new FrameworkPropertyMetadata(default(bool), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsTopDrawerOpenPropertyChangedCallback));
 
         public bool IsTopDrawerOpen
         {
@@ -164,6 +163,7 @@ public bool TopDrawerCloseOnClickAway
             get { return (bool)GetValue(TopDrawerCloseOnClickAwayProperty); }
             set { SetValue(TopDrawerCloseOnClickAwayProperty, value); }
         }
+
         #endregion
 
         #region left drawer
@@ -214,7 +214,7 @@ public Brush LeftDrawerBackground
         }
 
         public static readonly DependencyProperty IsLeftDrawerOpenProperty = DependencyProperty.Register(
-            nameof(IsLeftDrawerOpen), typeof(bool), typeof(DrawerHost), new FrameworkPropertyMetadata(default(bool), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsDrawerOpenPropertyChangedCallback));
+            nameof(IsLeftDrawerOpen), typeof(bool), typeof(DrawerHost), new FrameworkPropertyMetadata(default(bool), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsLeftDrawerOpenPropertyChangedCallback));
 
         public bool IsLeftDrawerOpen
         {
@@ -294,7 +294,7 @@ public Brush RightDrawerBackground
         }
 
         public static readonly DependencyProperty IsRightDrawerOpenProperty = DependencyProperty.Register(
-            nameof(IsRightDrawerOpen), typeof(bool), typeof(DrawerHost), new FrameworkPropertyMetadata(default(bool), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsDrawerOpenPropertyChangedCallback));
+            nameof(IsRightDrawerOpen), typeof(bool), typeof(DrawerHost), new FrameworkPropertyMetadata(default(bool), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsRightDrawerOpenPropertyChangedCallback));
 
         public bool IsRightDrawerOpen
         {
@@ -374,7 +374,7 @@ public Brush BottomDrawerBackground
         }
 
         public static readonly DependencyProperty IsBottomDrawerOpenProperty = DependencyProperty.Register(
-            nameof(IsBottomDrawerOpen), typeof(bool), typeof(DrawerHost), new FrameworkPropertyMetadata(default(bool), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsDrawerOpenPropertyChangedCallback));
+            nameof(IsBottomDrawerOpen), typeof(bool), typeof(DrawerHost), new FrameworkPropertyMetadata(default(bool), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, IsBottomDrawerOpenPropertyChangedCallback));
 
         public bool IsBottomDrawerOpen
         {
@@ -406,6 +406,56 @@ public bool BottomDrawerCloseOnClickAway
 
         #endregion
 
+        #region open drawer events/callbacks
+
+        public static readonly RoutedEvent DrawerOpenedEvent =
+            EventManager.RegisterRoutedEvent(
+                "DrawerOpened",
+                RoutingStrategy.Bubble,
+                typeof(EventHandler<DrawerOpenedEventArgs>),
+                typeof(DrawerHost));
+
+        /// <summary>
+        /// Raised when a drawer is opened.
+        /// </summary>
+        public event EventHandler<DrawerOpenedEventArgs> DrawerOpened
+        {
+            add { AddHandler(DrawerOpenedEvent, value); }
+            remove { RemoveHandler(DrawerOpenedEvent, value); }
+        }
+
+        protected void OnDrawerOpened(DrawerOpenedEventArgs eventArgs)
+        {
+            RaiseEvent(eventArgs);
+        }
+
+        #endregion
+
+        #region close drawer events/callbacks
+
+        public static readonly RoutedEvent DrawerClosingEvent =
+            EventManager.RegisterRoutedEvent(
+                "DrawerClosing",
+                RoutingStrategy.Bubble,
+                typeof(EventHandler<DrawerClosingEventArgs>),
+                typeof(DrawerHost));
+
+        /// <summary>
+        /// Raised when a drawer is closing.
+        /// </summary>
+        public event EventHandler<DrawerClosingEventArgs> DrawerClosing
+        {
+            add { AddHandler(DrawerClosingEvent, value); }
+            remove { RemoveHandler(DrawerClosingEvent, value); }
+        }
+
+        protected void OnDrawerClosing(DrawerClosingEventArgs eventArgs)
+        {
+            RaiseEvent(eventArgs);
+        }
+
+        #endregion
+
         public override void OnApplyTemplate()
         {
             if (_templateContentCoverElement != null)
@@ -500,12 +550,45 @@ private void UpdateVisualStates(bool? useTransitions = null)
                 IsBottomDrawerOpen ? TemplateBottomOpenStateName : TemplateBottomClosedStateName, useTransitions.HasValue ? useTransitions.Value : !TransitionAssist.GetDisableTransitions(this));
         }
 
-        private static void IsDrawerOpenPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        private static void IsTopDrawerOpenPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        {
+            IsDrawerOpenPropertyChanged(dependencyObject, dependencyPropertyChangedEventArgs, Dock.Top);
+        }
+
+        private static void IsLeftDrawerOpenPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        {
+            IsDrawerOpenPropertyChanged(dependencyObject, dependencyPropertyChangedEventArgs, Dock.Left);
+        }
+
+        private static void IsRightDrawerOpenPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        {
+            IsDrawerOpenPropertyChanged(dependencyObject, dependencyPropertyChangedEventArgs, Dock.Right);
+        }
+
+        private static void IsBottomDrawerOpenPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        {
+            IsDrawerOpenPropertyChanged(dependencyObject, dependencyPropertyChangedEventArgs, Dock.Bottom);
+        }
+
+        private static void IsDrawerOpenPropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs, Dock dock)
         {
             var drawerHost = (DrawerHost)dependencyObject;
             if (!drawerHost._lockZIndexes && (bool)dependencyPropertyChangedEventArgs.NewValue)
                 drawerHost.PrepareZIndexes(drawerHost._zIndexPropertyLookup[dependencyPropertyChangedEventArgs.Property]);
             drawerHost.UpdateVisualStates();
+
+            if ((bool)dependencyPropertyChangedEventArgs.NewValue)
+            {
+                RaiseDrawerOpened(drawerHost, dock);
+            }
+        }
+
+        private static void RaiseDrawerOpened(DrawerHost drawerHost, Dock dock)
+        {
+            //multiple ways of calling back that the drawer has opened:
+            // * routed event
+            var drawerOpenedEventArgs = new DrawerOpenedEventArgs(dock, DrawerOpenedEvent);
+            drawerHost.OnDrawerOpened(drawerOpenedEventArgs);
         }
 
         private void PrepareZIndexes(DependencyPropertyKey zIndexDependencyPropertyKey)
@@ -524,6 +607,19 @@ private void CloseDrawerHandler(object sender, ExecutedRoutedEventArgs executedR
         {
             if (executedRoutedEventArgs.Handled) return;
 
+            if (executedRoutedEventArgs.Parameter is Dock dock)
+            {
+                var drawerClosingEventArgs = new DrawerClosingEventArgs(dock, DrawerClosingEvent);
+                //multiple ways of calling back that the drawer is closing:
+                // * routed event
+                OnDrawerClosing(drawerClosingEventArgs);
+
+                if (drawerClosingEventArgs.IsCancelled)
+                {
+                    return;
+                }
+            }
+
             SetOpenFlag(executedRoutedEventArgs, false);
 
             executedRoutedEventArgs.Handled = true;

MaterialDesignThemes.Wpf/DrawerOpenedEventArgs.cs

@@ -0,0 +1,18 @@
+using System.Windows;
+using System.Windows.Controls;
+
+namespace MaterialDesignThemes.Wpf
+{
+    public class DrawerOpenedEventArgs : RoutedEventArgs
+    {
+        public DrawerOpenedEventArgs(Dock dock, RoutedEvent routedEvent) : base(routedEvent)
+        {
+            Dock = dock;
+        }
+
+        /// <summary>
+        /// Allows interation with the current dialog session.
+        /// </summary>
+        public Dock Dock { get; }
+    }
+}