Merge pull request #3988 from MahApps/fix/3986-ColorPicker-InvalidCas…

…tException-DefaultColor Fix InvalidCastException at ColorPicker when a DefaultColor is set
MahApps · Dec 1, 2020 · 821d15d · 821d15d
2 parents f0ba628 + ea03383
commit 821d15d
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Showing 3 changed files with 27 additions and 30 deletions.
diff --git a/src/MahApps.Metro.Samples/MahApps.Metro.Demo/ExampleViews/ColorPickerExample.xaml b/src/MahApps.Metro.Samples/MahApps.Metro.Demo/ExampleViews/ColorPickerExample.xaml
@@ -24,7 +24,7 @@
             </GroupBox>
 
             <GroupBox Margin="5 5 5 0" Header="Color Canvas">
-                <mah:ColorCanvas x:Name="ColorCanvasExample" SelectedColor="Blue" />
+                <mah:ColorCanvas x:Name="ColorCanvasExample" DefaultColor="{DynamicResource MahApps.Colors.AccentBase}" />
             </GroupBox>
 
             <GroupBox Margin="5" Header="Color Picker">

diff --git a/src/MahApps.Metro/Controls/ColorPicker/ColorPicker.cs b/src/MahApps.Metro/Controls/ColorPicker/ColorPicker.cs
@@ -758,9 +758,6 @@ internal override void OnSelectedColorChanged(Color? oldValue, Color? newValue)
         {
             base.OnSelectedColorChanged(newValue, oldValue);
 
-            // Set color is Updating again
-            this.ColorIsUpdating = true;
-
             this.PART_ColorPaletteAvailable?.SetCurrentValue(Selector.SelectedValueProperty, newValue);
             this.PART_ColorPaletteStandard?.SetCurrentValue(Selector.SelectedValueProperty, newValue);
             this.PART_ColorPaletteCustom01?.SetCurrentValue(Selector.SelectedValueProperty, newValue);
@@ -771,8 +768,6 @@ internal override void OnSelectedColorChanged(Color? oldValue, Color? newValue)
             {
                 BuildInColorPalettes.AddColorToRecentColors(newValue, this.RecentColorPaletteItemsSource, BuildInColorPalettes.GetMaximumRecentColorsCount(this));
             }
-
-            this.ColorIsUpdating = false;
         }
 
         private void ColorPalette_SelectionChanged(object sender, SelectionChangedEventArgs e)
@@ -841,10 +836,7 @@ private static void OnIsDropDownOpenChanged(DependencyObject d, DependencyProper
 
                     if (colorPicker.AddToRecentColorsTrigger == AddToRecentColorsTrigger.ColorPickerClosed && colorPicker.SelectedColor.HasValue)
                     {
-                        // We Update something so we need to flag this
-                        colorPicker.ColorIsUpdating = true;
                         BuildInColorPalettes.AddColorToRecentColors(colorPicker.SelectedColor, colorPicker.RecentColorPaletteItemsSource, BuildInColorPalettes.GetMaximumRecentColorsCount(colorPicker));
-                        colorPicker.ColorIsUpdating = false;
                     }
                 }
             }

diff --git a/src/MahApps.Metro/Controls/ColorPicker/ColorPickerBase.cs b/src/MahApps.Metro/Controls/ColorPicker/ColorPickerBase.cs
@@ -22,14 +22,26 @@ public static readonly DependencyProperty SelectedColorProperty
             = DependencyProperty.Register(nameof(SelectedColor),
                                           typeof(Color?),
                                           typeof(ColorPickerBase),
-                                          new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnSelectedColorPropertyChanged));
+                                          new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, OnSelectedColorPropertyChanged, CoerceSelectedColorProperty));
 
         private static void OnSelectedColorPropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
+        {
+            if (dependencyObject is ColorPickerBase colorPicker && e.OldValue != e.NewValue && !colorPicker.ColorIsUpdating)
+            {
+                colorPicker.ColorIsUpdating = true;
+                colorPicker.OnSelectedColorChanged(e.OldValue as Color?, e.NewValue as Color? ?? colorPicker.DefaultColor);
+                colorPicker.ColorIsUpdating = false;
+            }
+        }
+
+        private static object CoerceSelectedColorProperty(DependencyObject dependencyObject, object basevalue)
         {
             if (dependencyObject is ColorPickerBase colorPicker)
             {
-                colorPicker.OnSelectedColorChanged(e.OldValue as Color?, e.NewValue as Color?);
+                basevalue ??= colorPicker.DefaultColor;
             }
+
+            return basevalue;
         }
 
         /// <summary>
@@ -46,7 +58,15 @@ public static readonly DependencyProperty DefaultColorProperty
             = DependencyProperty.Register(nameof(DefaultColor),
                                           typeof(Color?),
                                           typeof(ColorPickerBase),
-                                          new FrameworkPropertyMetadata(null, OnSelectedColorPropertyChanged));
+                                          new FrameworkPropertyMetadata(null, OnDefaultColorPropertyChanged));
+
+        private static void OnDefaultColorPropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
+        {
+            if (dependencyObject is ColorPickerBase colorPicker && e.OldValue != e.NewValue)
+            {
+                colorPicker.SetCurrentValue(SelectedColorProperty, e.NewValue ?? colorPicker.SelectedColor);
+            }
+        }
 
         /// <summary>
         /// Gets or sets a default selected <see cref="Color"/>
@@ -411,25 +431,12 @@ public event RoutedPropertyChangedEventHandler<Color?> SelectedColorChanged
 
         internal virtual void OnSelectedColorChanged(Color? oldValue, Color? newValue)
         {
-            // don't do a second update
-            if (this.ColorIsUpdating)
-            {
-                return;
-            }
-
-            this.ColorIsUpdating = true;
-
-            if (this.SelectedColor == null && this.DefaultColor != null)
-            {
-                this.SetCurrentValue(SelectedColorProperty, this.DefaultColor);
-            }
-
-            this.SetCurrentValue(ColorNameProperty, ColorHelper.GetColorName(this.SelectedColor, this.ColorNamesDictionary));
+            this.SetCurrentValue(ColorNameProperty, ColorHelper.GetColorName(newValue, this.ColorNamesDictionary));
 
             // We just update the following lines if we have a Color.
-            if (this.SelectedColor != null)
+            if (newValue != null)
             {
-                var color = (Color)this.SelectedColor;
+                var color = (Color)newValue;
 
                 if (this.UpdateHsvValues)
                 {
@@ -447,8 +454,6 @@ internal virtual void OnSelectedColorChanged(Color? oldValue, Color? newValue)
                 this.SetCurrentValue(BProperty, color.B);
             }
 
-            this.ColorIsUpdating = false;
-
             this.RaiseEvent(new RoutedPropertyChangedEventArgs<Color?>(oldValue, newValue, SelectedColorChangedEvent));
         }