fixed some bugs

HandyControl/Controls/Carousel.cs

@@ -40,6 +40,14 @@ namespace HandyControl.Controls
 
         private ItemsPresenter _itemsControl;
 
+        private int _pageIndex = -1;
+
+        private Button _selectedButton;
+
+        private DispatcherTimer _updateTimer;
+
+        private readonly List<double> _widthList = new List<double>();
+
         #endregion Data
 
         public override void OnApplyTemplate()
@@ -63,7 +71,7 @@ namespace HandyControl.Controls
         private void Update()
         {
             TimerSwitch(AutoRun);
-            UpdatePageButtons();
+            UpdatePageButtons(_pageIndex);
         }
 
         private void CheckNull()
@@ -99,14 +107,6 @@ namespace HandyControl.Controls
             set => SetValue(IsCenterProperty, value);
         }
 
-        private int _pageIndex;
-
-        private Button _selectedButton;
-
-        private DispatcherTimer _updateTimer;
-
-        private readonly List<double> _widthList = new List<double>();
-
         public Carousel()
         {
             CommandBindings.Add(new CommandBinding(ControlCommands.Prev, ButtonPrev_OnClick));
@@ -167,24 +167,21 @@ namespace HandyControl.Controls
         private void TimerSwitch(bool run)
         {
             if (!_appliedTemplate) return;
-            if (run)
+
+            if (_updateTimer != null)
             {
-                _updateTimer = new DispatcherTimer
-                {
-                    Interval = Interval
-                };
-                _updateTimer.Tick += UpdateTimer_Tick;
-                _updateTimer.Start();
+                _updateTimer.Tick -= UpdateTimer_Tick;
+                _updateTimer.Stop();
+                _updateTimer = null;
             }
-            else
+
+            if (!run) return;
+            _updateTimer = new DispatcherTimer
             {
-                if (_updateTimer != null)
-                {
-                    _updateTimer.Tick -= UpdateTimer_Tick;
-                    _updateTimer.Stop();
-                    _updateTimer = null;
-                }
-            }
+                Interval = Interval
+            };
+            _updateTimer.Tick += UpdateTimer_Tick;
+            _updateTimer.Start();
         }
 
         private void UpdateTimer_Tick(object sender, EventArgs e)
@@ -196,40 +193,41 @@ namespace HandyControl.Controls
         /// <summary>
         ///     更新页按钮
         /// </summary>
-        public void UpdatePageButtons(int? index = null)
+        public void UpdatePageButtons(int index = -1)
         {
             if (!_appliedTemplate) return;
-            if (index == null)
-            {
-                var count = Items.Count;
-                _widthList.Clear();
-                _widthList.Add(0);
-                var width = .0;
-                foreach (FrameworkElement item in Items)
-                {
-                    item.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
-                    width += item.DesiredSize.Width;
-                    _widthList.Add(width);
-                }
 
-                _itemsControl.Width = _widthList.Last() + ExtendWidth;
-                _panelPage.Children.Clear();
-                for (var i = 0; i < count; i++)
-                    _panelPage.Children.Add(CreatePateButton());
+            var count = Items.Count;
+            _widthList.Clear();
+            _widthList.Add(0);
+            var width = .0;
+            foreach (FrameworkElement item in Items)
+            {
+                item.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
+                width += item.DesiredSize.Width;
+                _widthList.Add(width);
+            }
+
+            _itemsControl.Width = _widthList.Last() + ExtendWidth;
+            _panelPage.Children.Clear();
+            for (var i = 0; i < count; i++)
+            {
+                _panelPage.Children.Add(CreatePateButton());
+            }
+
+            if (index == -1)
+            {
                 if (count > 0)
                 {
                     var button = _panelPage.Children[0];
                     button.RaiseEvent(new RoutedEventArgs(ButtonBase.ClickEvent, button));
                 }
             }
-            else
+            else if (index >= 0 && index < count)
             {
-                if (index >= 0 && index < _panelPage.Children.Count)
-                {
-                    var button = _panelPage.Children[(int)index];
-                    button.RaiseEvent(new RoutedEventArgs(ButtonBase.ClickEvent, button));
-                    UpdateItemsPosition();
-                }
+                var button = _panelPage.Children[index];
+                button.RaiseEvent(new RoutedEventArgs(ButtonBase.ClickEvent, button));
+                UpdateItemsPosition();
             }
         }