Handle theme changes in ColorPickerSlider

Author: robloo

Microsoft.Toolkit.Uwp.UI.Controls.Input/ColorPicker/ColorPickerSlider.cs

@@ -2,9 +2,9 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using Microsoft.Toolkit.Uwp.Helpers;
 using Microsoft.Toolkit.Uwp.UI.Controls.ColorPickerConverters;
+using System;
 using Windows.Foundation;
 using Windows.UI;
 using Windows.UI.Xaml;
@@ -38,6 +38,8 @@ public ColorPickerSlider()
             : base()
         {
             this.DefaultStyleKey = typeof(ColorPickerSlider);
+
+            this.ActualThemeChanged += this.ColorPickerSlider_ActualThemeChanged;
         }
 
         /***************************************************************************************
@@ -297,5 +299,14 @@ private void OnDependencyPropertyChanged(object sender, DependencyPropertyChange
 
             return;
         }
+
+        /// <summary>
+        /// Event handler for when the control's theme changes.
+        /// </summary>
+        private void ColorPickerSlider_ActualThemeChanged(FrameworkElement sender, object args)
+        {
+            this.UpdateColors();
+            return;
+        }
     }
 }