Add CaretBrush property to Textbox

samples/ControlCatalog/Pages/TextBoxPage.xaml

@@ -26,6 +26,7 @@
         <TextBox Width="200" Text="Left aligned text" TextAlignment="Left" />
         <TextBox Width="200" Text="Center aligned text" TextAlignment="Center" />
         <TextBox Width="200" Text="Right aligned text" TextAlignment="Right" />
+        <TextBox Width="200" Text="Custom caret brush" CaretBrush="DarkOrange"/>
       </StackPanel>
 
       <StackPanel Orientation="Vertical" Spacing="8">

src/Avalonia.Controls/Presenters/TextPresenter.cs

@@ -19,6 +19,9 @@ namespace Avalonia.Controls.Presenters
         public static readonly StyledProperty<char> PasswordCharProperty =
             AvaloniaProperty.Register<TextPresenter, char>(nameof(PasswordChar));
 
+        public static readonly StyledProperty<IBrush> CaretBrushProperty =
+         AvaloniaProperty.Register<TextPresenter, IBrush>(nameof(CaretBrushProperty));
+
         public static readonly DirectProperty<TextPresenter, int> SelectionStartProperty =
             TextBox.SelectionStartProperty.AddOwner<TextPresenter>(
                 o => o.SelectionStart,
@@ -35,7 +38,7 @@ namespace Avalonia.Controls.Presenters
         private int _selectionEnd;
         private bool _caretBlink;
         private IBrush _highlightBrush;
-        
+
         static TextPresenter()
         {
             AffectsRender<TextPresenter>(PasswordCharProperty);
@@ -79,6 +82,12 @@ namespace Avalonia.Controls.Presenters
             set => SetValue(PasswordCharProperty, value);
         }
 
+        public IBrush CaretBrush
+        {
+            get => GetValue(CaretBrushProperty);
+            set => SetValue(CaretBrushProperty, value);
+        }
+
         public int SelectionStart
         {
             get
@@ -144,16 +153,21 @@ namespace Avalonia.Controls.Presenters
 
             if (selectionStart == selectionEnd)
             {
-                var backgroundColor = (((Control)TemplatedParent).GetValue(BackgroundProperty) as SolidColorBrush)?.Color;
-                var caretBrush = Brushes.Black;
+                var caretBrush = CaretBrush;
 
-                if (backgroundColor.HasValue)
+                if (caretBrush is null)
                 {
-                    byte red = (byte)~(backgroundColor.Value.R);
-                    byte green = (byte)~(backgroundColor.Value.G);
-                    byte blue = (byte)~(backgroundColor.Value.B);
-
-                    caretBrush = new SolidColorBrush(Color.FromRgb(red, green, blue));
+                    var backgroundColor = (((Control)TemplatedParent).GetValue(BackgroundProperty) as SolidColorBrush)?.Color;
+                    if (backgroundColor.HasValue)
+                    {
+                        byte red = (byte)~(backgroundColor.Value.R);
+                        byte green = (byte)~(backgroundColor.Value.G);
+                        byte blue = (byte)~(backgroundColor.Value.B);
+
+                        caretBrush = new SolidColorBrush(Color.FromRgb(red, green, blue));
+                    }
+                    else
+                        caretBrush = Brushes.Black;
                 }
 
                 if (_caretBlink)

src/Avalonia.Controls/TextBox.cs

@@ -38,6 +38,9 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<char> PasswordCharProperty =
             AvaloniaProperty.Register<TextBox, char>(nameof(PasswordChar));
 
+        public static readonly StyledProperty<IBrush> CaretBrushProperty =
+  AvaloniaProperty.Register<TextPresenter, IBrush>(nameof(CaretBrushProperty));
+
         public static readonly DirectProperty<TextBox, int> SelectionStartProperty =
             AvaloniaProperty.RegisterDirect<TextBox, int>(
                 nameof(SelectionStart),
@@ -169,6 +172,12 @@ namespace Avalonia.Controls
             set => SetValue(PasswordCharProperty, value);
         }
 
+        public IBrush CaretBrush
+        {
+            get => GetValue(CaretBrushProperty);
+            set => SetValue(CaretBrushProperty, value);
+        }
+
         public int SelectionStart
         {
             get

src/Avalonia.Themes.Default/TextBox.xaml

@@ -44,7 +44,8 @@
                                  SelectionEnd="{TemplateBinding SelectionEnd}"
                                  TextAlignment="{TemplateBinding TextAlignment}"
                                  TextWrapping="{TemplateBinding TextWrapping}"
-                                 PasswordChar="{TemplateBinding PasswordChar}"/>
+                                 PasswordChar="{TemplateBinding PasswordChar}"
+                                 CaretBrush="{TemplateBinding CaretBrush}"/>
                 </Panel>
               </ScrollViewer>
             </DataValidationErrors>