EnableDataValidation for TimePicker (#14406)

src/Avalonia.Controls/DateTimePickers/TimePicker.cs

@@ -44,7 +44,7 @@ namespace Avalonia.Controls
         /// </summary>
         public static readonly StyledProperty<TimeSpan?> SelectedTimeProperty =
             AvaloniaProperty.Register<TimePicker, TimeSpan?>(nameof(SelectedTime),
-                defaultBindingMode: BindingMode.TwoWay);
+                defaultBindingMode: BindingMode.TwoWay, enableDataValidation: true);
 
         // Template Items
         private TimePickerPresenter? _presenter;
@@ -290,5 +290,13 @@ namespace Avalonia.Controls
         {
             SetCurrentValue(SelectedTimeProperty, null);
         }
+
+        protected override void UpdateDataValidation(AvaloniaProperty property, BindingValueType state, Exception? error)
+        {
+            base.UpdateDataValidation(property, state, error);
+
+            if (property == SelectedTimeProperty)
+                DataValidationErrors.SetError(this, error);
+        }
     }
 }

tests/Avalonia.Controls.UnitTests/TimePickerTests.cs

@@ -1,9 +1,12 @@
 using System;
 using System.Linq;
+using System.Reactive.Subjects;
 using Avalonia.Controls.Shapes;
 using Avalonia.Controls.Templates;
+using Avalonia.Data;
 using Avalonia.Headless;
 using Avalonia.Platform;
+using Avalonia.Threading;
 using Avalonia.UnitTests;
 using Avalonia.VisualTree;
 using Moq;
@@ -133,6 +136,48 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void SelectedTime_EnableDataValidation()
+        {
+            using (UnitTestApplication.Start(Services))
+            {
+                var handled = false;
+                var timePicker = new TimePicker();
+
+                timePicker.SelectedTimeChanged += (s, e) =>
+                {
+                    var minTime = new TimeSpan(10, 0, 0);
+                    var maxTime = new TimeSpan(15, 0, 0);
+
+                    if (e.NewTime < minTime)
+                        throw new DataValidationException($"time is less than {maxTime}");
+
+                    if (e.NewTime > maxTime)
+                        throw new DataValidationException($"time is over {maxTime}");
+
+                    handled = true;
+                };
+
+                // time is less than
+                Assert.Throws<DataValidationException>(() => timePicker.SelectedTime = new TimeSpan(1, 2, 3));
+
+                // time is over
+                Assert.Throws<DataValidationException>(() => timePicker.SelectedTime = new TimeSpan(21, 22, 23));
+
+                var exception = new DataValidationException("failed validation");
+                var observable =
+                    new BehaviorSubject<BindingNotification>(new BindingNotification(exception,
+                        BindingErrorType.DataValidationError));
+                timePicker.Bind(TimePicker.SelectedTimeProperty, observable);
+
+                Assert.True(DataValidationErrors.GetHasErrors(timePicker));
+
+                Dispatcher.UIThread.RunJobs();
+                timePicker.SelectedTime = new TimeSpan(11, 12, 13);
+                Assert.True(handled);
+            }
+        }
+
         private static TestServices Services => TestServices.MockThreadingInterface.With(
             fontManagerImpl: new HeadlessFontManagerStub(),
             standardCursorFactory: Mock.Of<ICursorFactory>(),