From 75b0676d058de10a8bbb736f72378d3b50dac2bb Mon Sep 17 00:00:00 2001
From: shine <106159554+shine1258@users.noreply.github.com>
Date: Mon, 30 Mar 2026 15:58:02 +0800
Subject: [PATCH] Fix Placeholder not visible (#21024)

* Add default PlaceholderForeground to AutoCompleteBox, CalendarDatePicker and NumericUpDown.

* Add PlaceholderText template binding for simple theme ComboBox PART_EditableTextBox.
---
 src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml    | 1 +
 src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml | 1 +
 src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml      | 1 +
 src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml    | 1 +
 src/Avalonia.Themes.Simple/Controls/CalendarDatePicker.xaml | 1 +
 src/Avalonia.Themes.Simple/Controls/ComboBox.xaml           | 1 +
 src/Avalonia.Themes.Simple/Controls/NumericUpDown.xaml      | 1 +
 7 files changed, 7 insertions(+)

diff --git a/src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml b/src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml
index 92c46ecd41..bd9c84af17 100644
--- a/src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml
@@ -25,6 +25,7 @@
       <Setter Property="VerticalAlignment" Value="Top" />
       <Setter Property="Foreground" Value="{DynamicResource TextControlForeground}" />
       <Setter Property="Background" Value="{DynamicResource TextControlBackground}" />
+      <Setter Property="PlaceholderForeground" Value="{DynamicResource TextControlPlaceholderForeground}" />
       <Setter Property="BorderBrush" Value="{DynamicResource TextControlBorderBrush}" />
       <Setter Property="BorderThickness" Value="{DynamicResource TextControlBorderThemeThickness}" />
       <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
diff --git a/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml b/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
index 3a8db8ae36..395e2d514f 100644
--- a/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
@@ -63,6 +63,7 @@
   <ControlTheme x:Key="{x:Type CalendarDatePicker}" TargetType="CalendarDatePicker">
     <Setter Property="Background" Value="{DynamicResource CalendarDatePickerBackground}" />
     <Setter Property="Foreground" Value="{DynamicResource CalendarDatePickerForeground}" />
+    <Setter Property="PlaceholderForeground" Value="{DynamicResource TextControlPlaceholderForeground}" />
     <Setter Property="BorderBrush" Value="{DynamicResource CalendarDatePickerBorderBrush}" />
     <Setter Property="BorderThickness" Value="{DynamicResource CalendarDatePickerBorderThemeThickness}" />
     <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
diff --git a/src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml b/src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml
index b6c19484e9..bcd486534d 100644
--- a/src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml
@@ -52,6 +52,7 @@
   <ControlTheme x:Key="{x:Type NumericUpDown}" TargetType="NumericUpDown">
     <Setter Property="Foreground" Value="{DynamicResource TextControlForeground}" />
     <Setter Property="Background" Value="{DynamicResource TextControlBackground}" />
+    <Setter Property="PlaceholderForeground" Value="{DynamicResource TextControlPlaceholderForeground}" />
     <Setter Property="BorderThickness" Value="{DynamicResource TextControlBorderThemeThickness}" />
     <Setter Property="BorderBrush" Value="{DynamicResource TextControlBorderBrush}" />
     <Setter Property="MinHeight" Value="{DynamicResource TextControlThemeMinHeight}" />
diff --git a/src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml b/src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml
index ec0eccc8c4..7a1c98b598 100644
--- a/src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml
+++ b/src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml
@@ -4,6 +4,7 @@
   <ControlTheme x:Key="{x:Type AutoCompleteBox}"
                 TargetType="AutoCompleteBox">
     <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}" />
+    <Setter Property="PlaceholderForeground" Value="{DynamicResource ThemeForegroundLowBrush}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}" />
     <Setter Property="BorderThickness" Value="{DynamicResource ThemeBorderThickness}" />
     <Setter Property="Padding" Value="4" />
diff --git a/src/Avalonia.Themes.Simple/Controls/CalendarDatePicker.xaml b/src/Avalonia.Themes.Simple/Controls/CalendarDatePicker.xaml
index a38f6f912d..9eba0a413b 100644
--- a/src/Avalonia.Themes.Simple/Controls/CalendarDatePicker.xaml
+++ b/src/Avalonia.Themes.Simple/Controls/CalendarDatePicker.xaml
@@ -12,6 +12,7 @@
   <ControlTheme x:Key="{x:Type CalendarDatePicker}"
                 TargetType="CalendarDatePicker">
     <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}" />
+    <Setter Property="PlaceholderForeground" Value="{DynamicResource ThemeForegroundLowBrush}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}" />
     <Setter Property="BorderThickness" Value="{DynamicResource ThemeBorderThickness}" />
     <Setter Property="Padding" Value="4" />
diff --git a/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml b/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml
index 5a6266af6e..be4725d08c 100644
--- a/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml
+++ b/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml
@@ -50,6 +50,7 @@
                      Foreground="{TemplateBinding Foreground}"
                      Background="Transparent"
                      Text="{TemplateBinding Text, Mode=TwoWay}"
+                     PlaceholderText="{TemplateBinding PlaceholderText}"
                      BorderThickness="0"
                      IsVisible="{TemplateBinding IsEditable}">
               <TextBox.Resources>
diff --git a/src/Avalonia.Themes.Simple/Controls/NumericUpDown.xaml b/src/Avalonia.Themes.Simple/Controls/NumericUpDown.xaml
index 14cb0de6af..dbd01456bd 100644
--- a/src/Avalonia.Themes.Simple/Controls/NumericUpDown.xaml
+++ b/src/Avalonia.Themes.Simple/Controls/NumericUpDown.xaml
@@ -4,6 +4,7 @@
   <ControlTheme x:Key="{x:Type NumericUpDown}"
                 TargetType="NumericUpDown">
     <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}" />
+    <Setter Property="PlaceholderForeground" Value="{DynamicResource ThemeForegroundLowBrush}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}" />
     <Setter Property="BorderThickness" Value="{DynamicResource ThemeBorderThickness}" />
     <Setter Property="Padding" Value="4" />