feat: clean up code. add event to slider.

src/Ursa/Controls/RangeSlider/RangeSlider.cs

@@ -116,17 +116,38 @@ public class RangeSlider: TemplatedControl
         set => SetValue(IsSnapToTickProperty, value);
     }
     
+    public static readonly RoutedEvent<RangeValueChangedEventArgs> ValueChangedEvent =
+        RoutedEvent.Register<RangeSlider, RangeValueChangedEventArgs>(nameof(ValueChanged), RoutingStrategies.Bubble);
+    
+    public event EventHandler<RangeValueChangedEventArgs> ValueChanged
+    {
+        add => AddHandler(ValueChangedEvent, value);
+        remove => RemoveHandler(ValueChangedEvent, value);
+    } 
+    
     static RangeSlider()
     {
         PressedMixin.Attach<RangeSlider>();
         FocusableProperty.OverrideDefaultValue<RangeSlider>(true);
         IsHitTestVisibleProperty.OverrideDefaultValue<RangeSlider>(true);
         OrientationProperty.OverrideDefaultValue<RangeSlider>(Orientation.Horizontal);
-        OrientationProperty.Changed.AddClassHandler<RangeSlider, Avalonia.Layout.Orientation>((o,e)=>o.OnOrientationChanged(e));
+        OrientationProperty.Changed.AddClassHandler<RangeSlider, Orientation>((o,e)=>o.OnOrientationChanged(e));
         MinimumProperty.OverrideDefaultValue<RangeSlider>(0);
         MaximumProperty.OverrideDefaultValue<RangeSlider>(100);
         LowerValueProperty.OverrideDefaultValue<RangeSlider>(0);
         UpperValueProperty.OverrideDefaultValue<RangeSlider>(100);
+        LowerValueProperty.Changed.AddClassHandler<RangeSlider, double>((o, e) => o.OnValueChanged(e, true));
+        UpperValueProperty.Changed.AddClassHandler<RangeSlider, double>((o, e) => o.OnValueChanged(e, false));
+    }
+
+    private void OnValueChanged(AvaloniaPropertyChangedEventArgs<double> args, bool isLower)
+    {
+        var oldValue = args.OldValue.Value;
+        var newValue = args.NewValue.Value;
+        if (oldValue != newValue)
+        {
+            RaiseEvent(new RangeValueChangedEventArgs(ValueChangedEvent, this, oldValue, newValue, isLower));
+        }
     }
 
     public RangeSlider()

src/Ursa/Controls/RangeSlider/RangeTrack.cs

@@ -212,47 +212,17 @@ public class RangeTrack: Control
         var newThumb = args.NewValue.Value;
         if(oldThumb is not null)
         {
-            oldThumb.DragDelta -= OnThumbDragDelta;
             LogicalChildren.Remove(oldThumb);
             VisualChildren.Remove(oldThumb);
         }
         if (newThumb is not null)
         {
-            newThumb.DragDelta += OnThumbDragDelta;
             newThumb.ZIndex = 5;
             LogicalChildren.Add(newThumb);
             VisualChildren.Add(newThumb);
         }
     }
 
-    private void OnThumbDragDelta(object sender, VectorEventArgs e)
-    {
-        return;
-        if(sender is not Thumb thumb) return;
-        bool lower = thumb == LowerThumb;
-        double scale = IsDirectionReversed ? -1 : 1;
-        double originalValue = lower ? LowerValue : UpperValue;
-        double value;
-        if (Orientation == Orientation.Horizontal)
-        {
-            value = scale * e.Vector.X * _density;
-        }
-        else
-        {
-            value = -1 * scale * e.Vector.Y * _density;
-        }
-        var factor = e.Vector / value;
-        if (lower)
-        {
-            SetCurrentValue(LowerValueProperty, MathUtilities.Clamp(originalValue + value, Minimum, UpperValue));
-        }
-        else
-        {
-            SetCurrentValue(UpperValueProperty, MathUtilities.Clamp(originalValue + value, LowerValue, Maximum));
-        }
-        
-    }
-
     private void OnOrientationChanged(AvaloniaPropertyChangedEventArgs<Orientation> args)
     {
         Orientation o = args.NewValue.Value;
@@ -482,20 +452,6 @@ public class RangeTrack: Control
         return !double.IsInfinity(value) && !double.IsNaN(value);
     }
 
-    internal double GetThumbLength()
-    {
-        return Orientation == Orientation.Horizontal
-            ? LowerThumb?.Bounds.Width ?? 0 + UpperThumb?.Bounds.Width ?? 0
-            : LowerThumb?.Bounds.Height ?? 0 + UpperThumb?.Bounds.Height ?? 0;
-    }
-
-    internal double GetTrackLength()
-    {
-        return Orientation == Orientation.Horizontal
-            ? Bounds.Width
-            : Bounds.Height;
-    }
-
     internal double GetRatioByPoint(double position)
     {
         bool isHorizontal = Orientation == Orientation.Horizontal;