From 334be3ec74a54fb0c2932c995817f5dff93c0059 Mon Sep 17 00:00:00 2001
From: punker76 <punkerat76@gmail.com>
Date: Sun, 10 Nov 2024 14:18:46 +0100
Subject: [PATCH] fix: #17291 use CustomDateFormatString for parsing the text
 input

---
 .../CalendarDatePicker/CalendarDatePicker.cs  |  4 +-
 .../CalendarDatePickerTests.cs                | 63 +++++++++++++++++--
 2 files changed, 60 insertions(+), 7 deletions(-)

diff --git a/src/Avalonia.Controls/CalendarDatePicker/CalendarDatePicker.cs b/src/Avalonia.Controls/CalendarDatePicker/CalendarDatePicker.cs
index ec54533f4e1..85f035a604f 100644
--- a/src/Avalonia.Controls/CalendarDatePicker/CalendarDatePicker.cs
+++ b/src/Avalonia.Controls/CalendarDatePicker/CalendarDatePicker.cs
@@ -730,7 +730,9 @@ private void OpenDropDown()
             // the TextParseError event
             try
             {
-                newSelectedDate = DateTime.Parse(text, DateTimeHelper.GetCurrentDateFormat());
+                newSelectedDate = !string.IsNullOrEmpty(this.CustomDateFormatString) ?
+                    DateTime.ParseExact(text, this.CustomDateFormatString, DateTimeHelper.GetCurrentDateFormat()) :
+                    DateTime.Parse(text, DateTimeHelper.GetCurrentDateFormat());
 
                 if (Calendar.IsValidDateSelection(this._calendar!, newSelectedDate))
                 {
diff --git a/tests/Avalonia.Controls.UnitTests/CalendarDatePickerTests.cs b/tests/Avalonia.Controls.UnitTests/CalendarDatePickerTests.cs
index c3acf31caa7..ac6817233a4 100644
--- a/tests/Avalonia.Controls.UnitTests/CalendarDatePickerTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/CalendarDatePickerTests.cs
@@ -1,17 +1,13 @@
 using System;
-using System.Collections;
-using System.Collections.Generic;
-using System.ComponentModel;
 using System.Linq;
 using Avalonia.Controls.Primitives;
-using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Templates;
-using Avalonia.Data;
-using Avalonia.Markup.Data;
+using Avalonia.Input;
 using Avalonia.Platform;
 using Avalonia.UnitTests;
 using Moq;
 using Xunit;
+using System.Globalization;
 
 namespace Avalonia.Controls.UnitTests
 {
@@ -73,6 +69,34 @@ public void Adding_Blackout_Dates_Containing_Selected_Date_Should_Throw()
             }
         }
 
+        [Fact]
+        public void Setting_Date_Manually_With_CustomDateFormatString_Should_Be_Accepted()
+        {
+            CultureInfo.CurrentCulture = CultureInfo.CurrentUICulture = CultureInfo.GetCultureInfo("en-US");
+            using (UnitTestApplication.Start(Services))
+            {
+                CalendarDatePicker datePicker = CreateControl();
+                datePicker.SelectedDateFormat = CalendarDatePickerFormat.Custom;
+                datePicker.CustomDateFormatString = "dd.MM.yyyy";
+
+                var tb = GetTextBox(datePicker);
+
+                tb.Clear();
+                RaiseTextEvent(tb, "17.10.2024");
+                RaiseKeyEvent(tb, Key.Enter, KeyModifiers.None);
+                
+                Assert.Equal("17.10.2024", datePicker.Text);
+                Assert.True(CompareDates(datePicker.SelectedDate.Value, new DateTime(2024, 10, 17)));
+
+                tb.Clear();
+                RaiseTextEvent(tb, "12.10.2024");
+                RaiseKeyEvent(tb, Key.Enter, KeyModifiers.None);
+
+                Assert.Equal("12.10.2024", datePicker.Text);
+                Assert.True(CompareDates(datePicker.SelectedDate.Value, new DateTime(2024, 10, 12)));
+            }
+        }
+
         private static TestServices Services => TestServices.MockThreadingInterface.With(
             standardCursorFactory: Mock.Of<ICursorFactory>());
 
@@ -127,5 +151,32 @@ private static IControlTemplate CreateTemplate()
             });
 
         }
+
+        private TextBox GetTextBox(CalendarDatePicker control)
+        {
+            return control.GetTemplateChildren()
+                .OfType<TextBox>()
+                .First();
+        }
+
+        private static void RaiseKeyEvent(TextBox textBox, Key key, KeyModifiers inputModifiers)
+        {
+            textBox.RaiseEvent(new KeyEventArgs
+            {
+                RoutedEvent = InputElement.KeyDownEvent,
+                KeyModifiers = inputModifiers,
+                Key = key
+            });
+        }
+
+        private static void RaiseTextEvent(TextBox textBox, string text)
+        {
+            textBox.RaiseEvent(new TextInputEventArgs
+            {
+                RoutedEvent = InputElement.TextInputEvent,
+                Text = text
+            });
+        }
+
     }
 }