From daa8bd22dfde8a7da0ea735c431e30b419f03538 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Cruz?= <joaosantaremdacruz@tecnico.ulisboa.pt>
Date: Sun, 24 May 2026 12:17:31 +0100
Subject: [PATCH] Add VerticalContentAlignment property to DatePicker and
 TimePicker

This change registers VerticalContentAlignmentProperty as a
StyledProperty using ContentControl's property as the owner for both
DatePicker and TimePicker controls to maintain framework consistency.

Basic xUnit v3 unit tests are introduced to validate property
round-trips (Top, Center, Bottom, Stretch) and to ensure the default
value correctly resolves to Stretch. This establishes the necessary
C# infrastructure before modifying the control templates.

Part of #21211: implment fluent theme layout
---
 .../DateTimePickers/DatePicker.cs              | 15 +++++++++++++++
 .../DateTimePickers/TimePicker.cs              | 14 ++++++++++++++
 .../DatePickerTests.cs                         | 18 ++++++++++++++++++
 .../TimePickerTests.cs                         | 18 ++++++++++++++++++
 4 files changed, 65 insertions(+)

diff --git a/src/Avalonia.Controls/DateTimePickers/DatePicker.cs b/src/Avalonia.Controls/DateTimePickers/DatePicker.cs
index 2f406252f7..c4206c7315 100644
--- a/src/Avalonia.Controls/DateTimePickers/DatePicker.cs
+++ b/src/Avalonia.Controls/DateTimePickers/DatePicker.cs
@@ -75,6 +75,21 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<bool> YearVisibleProperty =
             AvaloniaProperty.Register<DatePicker, bool>(nameof(YearVisible), true);
 
+        /// <summary>
+        /// Defines the <see cref="VerticalContentAlignment"/> property.
+        /// </summary>
+        public static readonly StyledProperty<VerticalAlignment> VerticalContentAlignmentProperty =
+            ContentControl.VerticalContentAlignmentProperty.AddOwner<DatePicker>();
+
+        /// <summary>
+        /// Gets or sets the vertical alignment of the content within the control.
+        /// </summary>
+        public VerticalAlignment VerticalContentAlignment
+        {
+            get => GetValue(VerticalContentAlignmentProperty);
+            set => SetValue(VerticalContentAlignmentProperty, value);
+        }
+
         /// <summary>
         /// Defines the <see cref="SelectedDate"/> Property
         /// </summary>
diff --git a/src/Avalonia.Controls/DateTimePickers/TimePicker.cs b/src/Avalonia.Controls/DateTimePickers/TimePicker.cs
index 95d9e82782..7c6f96247f 100644
--- a/src/Avalonia.Controls/DateTimePickers/TimePicker.cs
+++ b/src/Avalonia.Controls/DateTimePickers/TimePicker.cs
@@ -50,6 +50,20 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<string> ClockIdentifierProperty =
            AvaloniaProperty.Register<TimePicker, string>(nameof(ClockIdentifier), "12HourClock", coerce: CoerceClockIdentifier);
         
+        /// <summary>
+        /// Defines the <see cref="VerticalContentAlignment"/> property.
+        /// </summary>
+        public static readonly StyledProperty<VerticalAlignment> VerticalContentAlignmentProperty =
+            ContentControl.VerticalContentAlignmentProperty.AddOwner<TimePicker>();
+
+        /// <summary>
+        /// Gets or sets the vertical alignment of the content within the control.
+        /// </summary>
+        public VerticalAlignment VerticalContentAlignment
+        {
+            get => GetValue(VerticalContentAlignmentProperty);
+            set => SetValue(VerticalContentAlignmentProperty, value);
+        }
         /// <summary>
         /// Defines the <see cref="UseSeconds"/> property
         /// </summary>
diff --git a/tests/Avalonia.Controls.UnitTests/DatePickerTests.cs b/tests/Avalonia.Controls.UnitTests/DatePickerTests.cs
index 4688a88fc5..523340a271 100644
--- a/tests/Avalonia.Controls.UnitTests/DatePickerTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/DatePickerTests.cs
@@ -371,6 +371,24 @@ namespace Avalonia.Controls.UnitTests
             });
         }
 
+        [Theory]
+        [InlineData(Avalonia.Layout.VerticalAlignment.Top)]
+        [InlineData(Avalonia.Layout.VerticalAlignment.Center)]
+        [InlineData(Avalonia.Layout.VerticalAlignment.Bottom)]
+        [InlineData(Avalonia.Layout.VerticalAlignment.Stretch)]
+        public void VerticalContentAlignment_RoundTrips(Avalonia.Layout.VerticalAlignment value)
+        {
+            var datePicker = new DatePicker { VerticalContentAlignment = value };
+            Assert.Equal(value, datePicker.VerticalContentAlignment);
+        }
+
+        [Fact]
+        public void VerticalContentAlignment_Default_Is_Stretch()
+        {
+            var datePicker = new DatePicker();
+            Assert.Equal(Avalonia.Layout.VerticalAlignment.Stretch, datePicker.VerticalContentAlignment);
+        }
+
         private static IControlTemplate CreatePickerTemplate()
         {
             return new FuncControlTemplate((_, scope) =>
diff --git a/tests/Avalonia.Controls.UnitTests/TimePickerTests.cs b/tests/Avalonia.Controls.UnitTests/TimePickerTests.cs
index 11c52392f1..2c16c19f60 100644
--- a/tests/Avalonia.Controls.UnitTests/TimePickerTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/TimePickerTests.cs
@@ -466,5 +466,23 @@ namespace Avalonia.Controls.UnitTests
                 return contentPanel;
             });
         }
+
+        [Theory]
+        [InlineData(Avalonia.Layout.VerticalAlignment.Top)]
+        [InlineData(Avalonia.Layout.VerticalAlignment.Center)]
+        [InlineData(Avalonia.Layout.VerticalAlignment.Bottom)]
+        [InlineData(Avalonia.Layout.VerticalAlignment.Stretch)]
+        public void VerticalContentAlignment_RoundTrips(Avalonia.Layout.VerticalAlignment value)
+        {
+            var timePicker = new TimePicker { VerticalContentAlignment = value };
+            Assert.Equal(value, timePicker.VerticalContentAlignment);
+        }
+
+        [Fact]
+        public void VerticalContentAlignment_Default_Is_Stretch()
+        {
+            var timePicker = new TimePicker();
+            Assert.Equal(Avalonia.Layout.VerticalAlignment.Stretch, timePicker.VerticalContentAlignment);
+        }
     }
 }