From 4ab5cc4bbdf0dda18db79db1d389867fa6f36d41 Mon Sep 17 00:00:00 2001
From: Dan Walmsley <dan@walms.co.uk>
Date: Mon, 23 Nov 2020 16:24:28 +0000
Subject: [PATCH] enable datavalidation on slider value property.

---
 src/Avalonia.Controls/Slider.cs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/Avalonia.Controls/Slider.cs b/src/Avalonia.Controls/Slider.cs
index 6e08e78813..fe4b24099f 100644
--- a/src/Avalonia.Controls/Slider.cs
+++ b/src/Avalonia.Controls/Slider.cs
@@ -3,6 +3,7 @@ using Avalonia.Collections;
 using Avalonia.Controls.Metadata;
 using Avalonia.Controls.Mixins;
 using Avalonia.Controls.Primitives;
+using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Layout;
@@ -94,6 +95,8 @@ namespace Avalonia.Controls
             Thumb.DragStartedEvent.AddClassHandler<Slider>((x, e) => x.OnThumbDragStarted(e), RoutingStrategies.Bubble);
             Thumb.DragCompletedEvent.AddClassHandler<Slider>((x, e) => x.OnThumbDragCompleted(e),
                 RoutingStrategies.Bubble);
+            
+            ValueProperty.OverrideMetadata<Slider>(new DirectPropertyMetadata<double>(enableDataValidation: true));
         }
 
         /// <summary>
@@ -225,6 +228,14 @@ namespace Avalonia.Controls
             Value = IsSnapToTickEnabled ? SnapToTick(finalValue) : finalValue;
         }
 
+        protected override void UpdateDataValidation<T>(AvaloniaProperty<T> property, BindingValue<T> value)
+        {
+            if (property == ValueProperty)
+            {
+                DataValidationErrors.SetError(this, value.Error);
+            }
+        }
+
         protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
         {
             base.OnPropertyChanged(change);