Default Date/Calendar picker dates

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/Given_CalendarDatePicker.cs

@@ -9,6 +9,8 @@
 using Microsoft.UI.Xaml.Controls.Primitives;
 using Microsoft.UI.Xaml.Media;
 using static Private.Infrastructure.TestServices;
+using Private.Infrastructure;
+using Uno.UI.RuntimeTests.MUX.Helpers;
 
 namespace Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml_Controls;
 
@@ -129,5 +131,28 @@ public async Task When_Theme_Changes()
 			}
 		}
 	}
+
+#if HAS_UNO
+	[TestMethod]
+	public async Task When_Default_Flyout_Date()
+	{
+		var now = DateTimeOffset.UtcNow;
+		var datePicker = new Microsoft.UI.Xaml.Controls.CalendarDatePicker();
+
+		TestServices.WindowHelper.WindowContent = datePicker;
+
+		await TestServices.WindowHelper.WaitForLoaded(datePicker);
+
+		datePicker.IsCalendarOpen = true;
+
+		await WindowHelper.WaitFor(() => VisualTreeHelper.GetOpenPopupsForXamlRoot(datePicker.XamlRoot).Count > 0);
+		var popup = VisualTreeHelper.GetOpenPopupsForXamlRoot(datePicker.XamlRoot).First();
+		var child = (FlyoutPresenter)popup.Child;
+		var calendarView = (CalendarView)child.Content;
+		Assert.AreEqual(now.Day, calendarView.m_lastDisplayedDate.Day);
+		Assert.AreEqual(now.Month, calendarView.m_lastDisplayedDate.Month);
+		Assert.AreEqual(now.Year, calendarView.m_lastDisplayedDate.Year);
+	}
+#endif
 }
 #endif

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/Given_DatePicker.cs

@@ -5,7 +5,6 @@
 using System.Threading.Tasks;
 using FluentAssertions;
 using FluentAssertions.Execution;
-using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Automation.Peers;
 using Microsoft.UI.Xaml.Automation.Provider;
 using Microsoft.UI.Xaml.Controls;
@@ -346,6 +345,41 @@ private async Task When_Flyout_Closed_FlyoutBase_Closed_Invoked(bool useNative)
 #endif
 		}
 
+#if __ANDROID__ || __IOS__
+		[TestMethod]
+		public async Task When_Default_Flyout_Date_Native()
+		{
+			var now = DateTimeOffset.UtcNow;
+			var datePicker = new Microsoft.UI.Xaml.Controls.DatePicker();
+			datePicker.UseNativeStyle = true;
+
+			TestServices.WindowHelper.WindowContent = datePicker;
+
+			await TestServices.WindowHelper.WaitForLoaded(datePicker);
+
+			await DateTimePickerHelper.OpenDateTimePicker(datePicker);
+
+			var openFlyouts = FlyoutBase.OpenFlyouts;
+			Assert.AreEqual(1, openFlyouts.Count);
+			var associatedFlyout = openFlyouts[0];
+			Assert.IsInstanceOfType(associatedFlyout, typeof(Microsoft.UI.Xaml.Controls.NativeDatePickerFlyout));
+
+			var datePickerFlyout = (NativeDatePickerFlyout)associatedFlyout;
+
+			try
+			{
+				Assert.AreEqual(DatePicker.NullDateSentinelValue, datePickerFlyout.Date);
+				Assert.AreEqual(now.Day, datePickerFlyout.NativeDialogDate.Day);
+				Assert.AreEqual(now.Month, datePickerFlyout.NativeDialogDate.Month);
+				Assert.AreEqual(now.Year, datePickerFlyout.NativeDialogDate.Year);
+			}
+			finally
+			{
+				datePickerFlyout.Close();
+			}
+		}
+#endif
+
 #if __IOS__
 		[TestMethod]
 		[UnoWorkItem("https://github.com/unoplatform/uno/issues/15263")]

src/Uno.UI/UI/Xaml/Controls/CalendarView/CalendarView_Partial.cs

@@ -59,7 +59,7 @@ public partial class CalendarView : Control
 		// 1. display Date if it is requested, if it is not requested, then
 		// 2. Today, if Today is not in given min/max range, then
 		// 3. the closest date to Today (i.e. the coerced date of Today)
-		DateTime m_lastDisplayedDate;
+		internal DateTime m_lastDisplayedDate;
 
 		DateTime m_today;
 		// m_minDate and m_maxDate are effective min/max dates, which could be different

src/Uno.UI/UI/Xaml/Controls/DatePicker/DatePicker.cs

@@ -2269,7 +2269,7 @@ void RefreshFlyoutButtonAutomationName()
 
 		/* static */
 
-		private static DateTimeOffset NullDateSentinelValue { get; } =
+		internal static DateTimeOffset NullDateSentinelValue { get; } =
 			default(WindowsFoundationDateTime);
 
 		void GetTodaysDate(out DateTimeOffset? todaysDate)

src/Uno.UI/UI/Xaml/Controls/DatePicker/NativeDatePickerFlyout.Android.cs

@@ -38,13 +38,15 @@ public NativeDatePickerFlyout()
 
 		internal bool IsNativeDialogOpen => _dialog?.IsShowing ?? false;
 
+		internal DateTimeOffset NativeDialogDate => _dialog.DatePicker.DateTime;
+
 		protected internal override void Open()
 		{
 			var date = Date;
 			// If we're setting the date to the null sentinel value,
 			// we'll instead set it to the current date for the purposes
 			// of where to place the user's position in the looping selectors.
-			if (date.Ticks == DatePicker.DEFAULT_DATE_TICKS)
+			if (date == DatePicker.NullDateSentinelValue)
 			{
 				var temp = new global::Windows.Globalization.Calendar();
 				var calendar = new global::Windows.Globalization.Calendar(

src/Uno.UI/UI/Xaml/Controls/DatePicker/NativeDatePickerFlyout.iOS.cs

@@ -37,6 +37,8 @@ private NativeDatePickerFlyoutPresenter _presenter
 
 		internal bool IsNativeDialogOpen { get; private set; }
 
+		internal DateTimeOffset NativeDialogDate => _selector.Date;
+
 		public static DependencyProperty UseNativeMinMaxDatesProperty { get; } = DependencyProperty.Register(
 			"UseNativeMinMaxDates",
 			typeof(bool),
@@ -145,7 +147,7 @@ private void DatePickerFlyout_Opening(object sender, object e)
 			// If we're setting the date to the null sentinel value,
 			// we'll instead set it to the current date for the purposes
 			// of where to place the user's position in the looping selectors.
-			if (date.Ticks == DatePicker.DEFAULT_DATE_TICKS)
+			if (date == DatePicker.NullDateSentinelValue)
 			{
 				var temp = new global::Windows.Globalization.Calendar();
 				var calendar = new global::Windows.Globalization.Calendar(