style building

src/Shared/HandyControl_Shared/Controls/SideMenu/SideMenu.cs

@@ -1,4 +1,5 @@
 using System.Windows;
+using HandyControl.Data;
 
 namespace HandyControl.Controls
 {
@@ -6,6 +7,41 @@ namespace HandyControl.Controls
     {
         private SideMenuItem _selectedItem;
 
+        private SideMenuItem _selectedHeader;
+
+        public SideMenu()
+        {
+            AddHandler(SideMenuItem.SelectedEvent, new RoutedEventHandler(SideMenuItemSelected));
+        }
+
+        private void SideMenuItemSelected(object sender, RoutedEventArgs e)
+        {
+            if (e.OriginalSource is SideMenuItem item)
+            {
+                if (item.Role == SideMenuItemRole.Item)
+                {
+                    if (_selectedItem != null)
+                    {
+                        _selectedItem.IsSelected = false;
+                    }
+
+                    _selectedItem = item;
+                    _selectedItem.IsSelected = true;
+                }
+                else
+                {
+                    if (_selectedHeader != null)
+                    {
+                        _selectedHeader.IsSelected = false;
+                    }
+
+                    _selectedHeader = item;
+                    _selectedHeader.IsSelected = true;
+                    _selectedHeader.SelectDefaultItem(_selectedItem);
+                }
+            }
+        }
+
         protected override DependencyObject GetContainerForItemOverride() => new SideMenuItem();
 
         protected override bool IsItemItsOwnContainerOverride(object item) => item is SideMenuItem;

src/Shared/HandyControl_Shared/Controls/SideMenu/SideMenuItem.cs

@@ -1,10 +1,14 @@
-using System.Windows;
+using System.Linq;
+using System.Windows;
+using System.Windows.Input;
 using HandyControl.Data;
 
 namespace HandyControl.Controls
 {
     public class SideMenuItem : HeaderedSimpleItemsControl, ISelectable
     {
+        private bool _isMouseLeftButtonDown;
+
         public static readonly DependencyProperty IconProperty = DependencyProperty.Register(
             "Icon", typeof(object), typeof(SideMenuItem), new PropertyMetadata(default(object)));
 
@@ -35,21 +39,59 @@ namespace HandyControl.Controls
             set => SetValue(IsSelectedProperty, value);
         }
 
-        private static readonly DependencyPropertyKey RolePropertyKey =
-            DependencyProperty.RegisterReadOnly(nameof(Role), typeof(SideMenuItemRole), typeof(SideMenuItem),
-                new PropertyMetadata(SideMenuItemRole.Header));
+        public static readonly DependencyProperty RoleProperty = DependencyProperty.Register(
+            "Role", typeof(SideMenuItemRole), typeof(SideMenuItem), new PropertyMetadata(default(SideMenuItemRole)));
 
-        public static readonly DependencyProperty RoleProperty = RolePropertyKey.DependencyProperty;
-
-        public SideMenuItemRole Role => (SideMenuItemRole) GetValue(RoleProperty);
+        public SideMenuItemRole Role
+        {
+            get => (SideMenuItemRole) GetValue(RoleProperty);
+            internal set => SetValue(RoleProperty, value);
+        }
 
         protected override DependencyObject GetContainerForItemOverride() => new SideMenuItem();
 
         protected override bool IsItemItsOwnContainerOverride(object item) => item is SideMenuItem;
 
-        private void UpdateRole()
+        protected override void OnMouseLeave(MouseEventArgs e)
         {
-            
+            base.OnMouseLeave(e);
+
+            _isMouseLeftButtonDown = false;
+        }
+
+        protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
+        {
+            base.OnMouseLeftButtonDown(e);
+
+            _isMouseLeftButtonDown = true;
+        }
+
+        protected override void OnMouseLeftButtonUp(MouseButtonEventArgs e)
+        {
+            base.OnMouseLeftButtonUp(e);
+
+            if (_isMouseLeftButtonDown)
+            {
+                if (!IsSelected)
+                {
+                    IsSelected = true;
+                    OnSelected(new RoutedEventArgs(SelectedEvent, this));
+                }
+                _isMouseLeftButtonDown = false;
+            }
+        }
+
+        internal void SelectDefaultItem(SideMenuItem menuItem)
+        {
+            if (Role == SideMenuItemRole.Header && ItemsHost.Children.Count > 0)
+            {
+                if (ItemsHost.Children.Contains(menuItem)) return;
+                var item = ItemsHost.Children.OfType<SideMenuItem>().FirstOrDefault();
+                if (item != null && !item.IsSelected)
+                {
+                    item.OnSelected(new RoutedEventArgs(SelectedEvent, item));
+                }
+            }
         }
     }
 }