Fix issue where scroll bar thumb color didn’t always change with theme

Kinnara · Dec 12, 2019 · 289113b · 289113b
1 parent 5e604fb
commit 289113b
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Showing 2 changed files with 37 additions and 0 deletions.
diff --git a/ModernWpf/Controls/Primitives/ScrollBarThumbHelper.cs b/ModernWpf/Controls/Primitives/ScrollBarThumbHelper.cs
@@ -0,0 +1,25 @@
+using System.Windows;
+using System.Windows.Controls.Primitives;
+
+namespace ModernWpf.Controls.Primitives
+{
+    public static class ScrollBarThumbHelper
+    {
+        public static readonly DependencyProperty IsExpandedProperty =
+            DependencyProperty.RegisterAttached(
+                "IsExpanded",
+                typeof(bool),
+                typeof(ScrollBarThumbHelper),
+                new PropertyMetadata(false));
+
+        public static bool GetIsExpanded(Thumb thumb)
+        {
+            return (bool)thumb.GetValue(IsExpandedProperty);
+        }
+
+        public static void SetIsExpanded(Thumb thumb, bool value)
+        {
+            thumb.SetValue(IsExpandedProperty, value);
+        }
+    }
+}
diff --git a/ModernWpf/Styles/ScrollBar.xaml b/ModernWpf/Styles/ScrollBar.xaml
@@ -149,6 +149,9 @@
             RadiusY="{TemplateBinding primitives:ControlHelper.CornerRadius, Converter={StaticResource BottomRightCornerRadiusDoubleValueConverter}}"
             SnapsToDevicePixels="True" />
         <ControlTemplate.Triggers>
+            <Trigger Property="primitives:ScrollBarThumbHelper.IsExpanded" Value="True">
+                <Setter TargetName="ThumbVisual" Property="Fill" Value="{DynamicResource ScrollBarThumbBackground}" />
+            </Trigger>
             <Trigger Property="IsMouseOver" Value="True">
                 <Setter TargetName="ThumbVisual" Property="Fill" Value="{DynamicResource ScrollBarThumbFillPointerOver}" />
             </Trigger>
@@ -170,6 +173,9 @@
             RadiusY="{TemplateBinding primitives:ControlHelper.CornerRadius, Converter={StaticResource BottomRightCornerRadiusDoubleValueConverter8x}}"
             SnapsToDevicePixels="True" />
         <ControlTemplate.Triggers>
+            <Trigger Property="primitives:ScrollBarThumbHelper.IsExpanded" Value="True">
+                <Setter TargetName="ThumbVisual" Property="Fill" Value="{DynamicResource ScrollBarThumbBackground}" />
+            </Trigger>
             <Trigger Property="IsMouseOver" Value="True">
                 <Setter TargetName="ThumbVisual" Property="Fill" Value="{DynamicResource ScrollBarThumbFillPointerOver}" />
             </Trigger>
@@ -319,6 +325,9 @@
                                         </DiscreteObjectKeyFrame.Value>
                                     </DiscreteObjectKeyFrame>
                                 </ObjectAnimationUsingKeyFrames>
+                                <BooleanAnimationUsingKeyFrames Storyboard.TargetName="VerticalThumb" Storyboard.TargetProperty="(primitives:ScrollBarThumbHelper.IsExpanded)">
+                                    <DiscreteBooleanKeyFrame KeyTime="0:0:0.5" Value="True" />
+                                </BooleanAnimationUsingKeyFrames>
                             </Storyboard>
                         </Border.Resources>
                         <VisualStateManager.VisualStateGroups>
@@ -552,6 +561,9 @@
                                                 </DiscreteObjectKeyFrame.Value>
                                             </DiscreteObjectKeyFrame>
                                         </ObjectAnimationUsingKeyFrames>
+                                        <BooleanAnimationUsingKeyFrames Storyboard.TargetName="HorizontalThumb" Storyboard.TargetProperty="(primitives:ScrollBarThumbHelper.IsExpanded)">
+                                            <DiscreteBooleanKeyFrame KeyTime="0:0:0.5" Value="True" />
+                                        </BooleanAnimationUsingKeyFrames>
                                     </Storyboard>
                                 </Border.Resources>
                                 <VisualStateManager.VisualStateGroups>