From 5da085ee20ebbfbb3e11a84f945533abc547141e Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sun, 5 Jul 2026 21:08:46 +0000
Subject: [PATCH 1/2] Initial plan


From 8fc5a7f20f522ffdf4afcd38bdaf9d7aa00da975 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sun, 5 Jul 2026 21:13:52 +0000
Subject: [PATCH 2/2] Derive default date/time formats from user profile
 language (#109)

---
 src/Columns/TableViewDateColumn.cs | 12 ++++++++++++
 src/Columns/TableViewTimeColumn.cs |  5 +++--
 tests/TableViewTimeColumnTests.cs  |  5 +++--
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/Columns/TableViewDateColumn.cs b/src/Columns/TableViewDateColumn.cs
index 1c3db4e6..ee273fe2 100644
--- a/src/Columns/TableViewDateColumn.cs
+++ b/src/Columns/TableViewDateColumn.cs
@@ -2,6 +2,8 @@
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Data;
 using System;
+using Windows.Globalization.DateTimeFormatting;
+using Windows.System.UserProfile;
 using WinUI.TableView.Controls;
 using WinUI.TableView.Extensions;
 using WinUI.TableView.Helpers;
@@ -19,6 +21,16 @@ namespace WinUI.TableView;
 #endif
 public partial class TableViewDateColumn : TableViewBoundColumn
 {
+    /// <summary>
+    /// Initializes a new instance of the TableViewDateColumn class.
+    /// </summary>
+    public TableViewDateColumn()
+    {
+        var languages = GlobalizationPreferences.Languages;
+        var patterns = languages.Count > 0 ? new DateTimeFormatter("shortdate", languages).Patterns : null;
+        DateFormat = patterns?.Count > 0 ? patterns[0] : "shortdate";
+    }
+
     /// <summary>
     /// Generates a TextBlock element for the cell.
     /// </summary>
diff --git a/src/Columns/TableViewTimeColumn.cs b/src/Columns/TableViewTimeColumn.cs
index bf5ef184..d07a0b3d 100644
--- a/src/Columns/TableViewTimeColumn.cs
+++ b/src/Columns/TableViewTimeColumn.cs
@@ -2,7 +2,7 @@
 using Microsoft.UI.Xaml.Controls;
 using Microsoft.UI.Xaml.Data;
 using System;
-using Windows.Globalization.DateTimeFormatting;
+using Windows.System.UserProfile;
 using WinUI.TableView.Controls;
 using WinUI.TableView.Extensions;
 using WinUI.TableView.Helpers;
@@ -24,7 +24,8 @@ public partial class TableViewTimeColumn : TableViewBoundColumn
     /// </summary>
     public TableViewTimeColumn()
     {
-        ClockIdentifier = DateTimeFormatter.LongTime.Clock;
+        var clocks = GlobalizationPreferences.Clocks;
+        ClockIdentifier = clocks.Count > 0 ? clocks[0] : "24HourClock";
     }
 
     /// <summary>
diff --git a/tests/TableViewTimeColumnTests.cs b/tests/TableViewTimeColumnTests.cs
index 1a6f4798..70b26e7e 100644
--- a/tests/TableViewTimeColumnTests.cs
+++ b/tests/TableViewTimeColumnTests.cs
@@ -4,7 +4,7 @@
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Microsoft.VisualStudio.TestTools.UnitTesting.AppContainer;
 using System;
-using Windows.Globalization.DateTimeFormatting;
+using Windows.System.UserProfile;
 using WinUI.TableView.Controls;
 using WinUI.TableView.Helpers;
 
@@ -33,7 +33,8 @@ public void TableViewTimeColumn_GeneratesEditingElementWithConfiguredProperties(
         Assert.AreEqual(TableViewLocalizedStrings.TimePickerPlaceholder, element.PlaceholderText);
         Assert.AreEqual(typeof(TimeOnly), element.SourceType);
         Assert.AreEqual(item.AppointmentTime, column.PrepareCellForEdit(cell, new RoutedEventArgs()));
-        Assert.AreEqual(DateTimeFormatter.LongTime.Clock, new TableViewTimeColumn().ClockIdentifier);
+        var clocks = GlobalizationPreferences.Clocks;
+        Assert.AreEqual(clocks.Count > 0 ? clocks[0] : "24HourClock", new TableViewTimeColumn().ClockIdentifier);
     }
 
     [UITestMethod]