Fix bug with changing focus and apply changes from microsoft#157, Closes

microsoft#200
marcelwgn · Sep 10, 2019 · c98fb90 · c98fb90
1 parent f0d4907
commit c98fb90
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Showing 2 changed files with 56 additions and 2 deletions.
diff --git a/XamlControlsGallery/ControlPages/SplitButtonPage.xaml b/XamlControlsGallery/ControlPages/SplitButtonPage.xaml
@@ -88,7 +88,11 @@
                     </muxcontrols:SplitButton.Flyout>
                 </muxcontrols:SplitButton>
 
-                <RichEditBox x:Name="myRichEditBox" Grid.Column="1" MinWidth="240" MinHeight="96" PlaceholderText="Type something here" TextChanged="MyRichEditBox_TextChanged"/>
+                <RichEditBox x:Name="myRichEditBox" Grid.Column="1" MinWidth="240" MinHeight="96" 
+                             PlaceholderText="Type something here" 
+                             GotFocus="MyRichEditBox_GotFocus"
+                             LosingFocus="MyRichEditBox_LosingFocus"
+                             TextChanging="MyRichEditBox_TextChanging"/>
             </Grid>
         </local:ControlExample>
     </StackPanel>

diff --git a/XamlControlsGallery/ControlPages/SplitButtonPage.xaml.cs b/XamlControlsGallery/ControlPages/SplitButtonPage.xaml.cs
@@ -1,4 +1,5 @@
 using Windows.UI;
+using Windows.UI.Text;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Media;
@@ -9,6 +10,11 @@ public sealed partial class SplitButtonPage : Page
     {
         private Color currentColor = Colors.Black;
 
+        // String used to restore the colors when the focus gets reenabled
+        // See #144 for more info https://github.com/microsoft/Xaml-Controls-Gallery/issues/144 
+        // (which also applies to this RichEditBox)
+        private string LastFormattedText = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, " +
+                "sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Tempor commodo ullamcorper a lacus.";
         public SplitButtonPage()
         {
             this.InitializeComponent();
@@ -41,9 +47,53 @@ private void myColorButton_Click(Microsoft.UI.Xaml.Controls.SplitButton sender,
             currentColor = color;
         }
 
-        private void MyRichEditBox_TextChanged(object sender, RoutedEventArgs e)
+        private void MyRichEditBox_TextChanging(object sender, RichEditBoxTextChangingEventArgs e)
         {
+            // Hitting control+b and similiar commands my overwrite the color,
+            // which result to black text on black background when losing focus on dark theme.
+            // Solution: check if text actually changed
+            if (e.IsContentChanging)
+            {
+                myRichEditBox.Document.Selection.CharacterFormat.ForegroundColor = currentColor;
+            }
+        }
+
+
+        private void MyRichEditBox_GotFocus(object sender, RoutedEventArgs e)
+        {
+            // reset colors to correct defaults for Focused state
+            ITextRange documentRange = myRichEditBox.Document.GetRange(0, TextConstants.MaxUnitCount);
+            SolidColorBrush background = (SolidColorBrush)App.Current.Resources["TextControlBackgroundFocused"];
+            SolidColorBrush foreground = (SolidColorBrush)App.Current.Resources["TextControlForegroundFocused"];
+
+            myRichEditBox.Document.ApplyDisplayUpdates();
+
+            if (background != null && foreground != null)
+            {
+                documentRange.CharacterFormat.BackgroundColor = background.Color;
+            }
+            // saving selection span
+            var caretPosition = myRichEditBox.Document.Selection.GetIndex(TextRangeUnit.Character) - 1;
+            if (caretPosition <= 0)
+            {
+                // User has not entered text, prevent invalid values and just set index to 1
+                caretPosition = 1;
+            }
+            var selectionLength = myRichEditBox.Document.Selection.Length;
+            // restoring text styling, unintentionally sets caret position at beginning of text
+            myRichEditBox.Document.SetText(TextSetOptions.FormatRtf, LastFormattedText);
+            // restoring selection position
+            myRichEditBox.Document.Selection.SetIndex(TextRangeUnit.Character, caretPosition, false);
+            myRichEditBox.Document.Selection.SetRange(caretPosition, caretPosition + selectionLength);
+            // Editor might have gained focus because user changed color.
+            // Change selection color
+            // Note that only way to regain with selection containing text is using the change color button
             myRichEditBox.Document.Selection.CharacterFormat.ForegroundColor = currentColor;
         }
+
+        private void MyRichEditBox_LosingFocus(object sender, RoutedEventArgs e)
+        {
+            myRichEditBox.Document.GetText(TextGetOptions.FormatRtf, out LastFormattedText);
+        }
     }
 }