From ff5f4804e2035602b0a7f7c306ef480c35a16581 Mon Sep 17 00:00:00 2001
From: usUyGBx <64971385+usUyGBx@users.noreply.github.com>
Date: Sun, 31 May 2020 22:04:24 +0300
Subject: [PATCH] Fix AutoCompleteBox validation

---
 src/Avalonia.Controls/AutoCompleteBox.cs | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/Avalonia.Controls/AutoCompleteBox.cs b/src/Avalonia.Controls/AutoCompleteBox.cs
index 3e4f47ec8a..c62ad3030e 100644
--- a/src/Avalonia.Controls/AutoCompleteBox.cs
+++ b/src/Avalonia.Controls/AutoCompleteBox.cs
@@ -467,10 +467,11 @@ namespace Avalonia.Controls
         /// <see cref="P:Avalonia.Controls.AutoCompleteBox.Text" />
         /// dependency property.</value>
         public static readonly DirectProperty<AutoCompleteBox, string> TextProperty =
-            AvaloniaProperty.RegisterDirect<AutoCompleteBox, string>(
-                nameof(Text),
+            TextBlock.TextProperty.AddOwnerWithDataValidation<AutoCompleteBox>(
                 o => o.Text,
-                (o, v) => o.Text = v);
+                (o, v) => o.Text = v,
+                defaultBindingMode: BindingMode.TwoWay,
+                enableDataValidation: true);
 
         /// <summary>
         /// Identifies the
@@ -1242,6 +1243,20 @@ namespace Avalonia.Controls
 
             base.OnApplyTemplate(e);
         }
+        
+        /// <summary>
+        /// Called to update the validation state for properties for which data validation is
+        /// enabled.
+        /// </summary>
+        /// <param name="property">The property.</param>
+        /// <param name="value">The new binding value for the property.</param>
+        protected override void UpdateDataValidation<T>(AvaloniaProperty<T> property, BindingValue<T> value)
+        {
+            if (property == TextProperty)
+            {
+                DataValidationErrors.SetError(this, value.Error);
+            }
+        }
 
         /// <summary>
         /// Provides handling for the