From be08931b47c70a0dfb142d8eff1cd954f908bffa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=A8=E5=8A=BC?= <yangjie123098@live.cn>
Date: Tue, 16 Sep 2025 18:02:37 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BF=AE=E5=A4=8D=20ImageViewer.Source=20?=
 =?UTF-8?q?=E8=AE=BE=E7=BD=AE=E4=B8=BAnull=E4=BC=9A=E6=8A=A5=E9=94=99?=
 =?UTF-8?q?=E7=9A=84=E9=97=AE=E9=A2=98=20=E4=BF=AE=E5=A4=8D=20https://gith?=
 =?UTF-8?q?ub.com/irihitech/Ursa.Avalonia/issues/680?=
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---
 demo/Ursa.Demo/Pages/ImageViewerDemo.axaml    | 12 ++++++++++--
 demo/Ursa.Demo/Pages/ImageViewerDemo.axaml.cs | 15 +++++++++++++++
 src/Ursa/Controls/ImageViewer/ImageViewer.cs  |  4 ++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/demo/Ursa.Demo/Pages/ImageViewerDemo.axaml b/demo/Ursa.Demo/Pages/ImageViewerDemo.axaml
index 85db8e6..0996338 100644
--- a/demo/Ursa.Demo/Pages/ImageViewerDemo.axaml
+++ b/demo/Ursa.Demo/Pages/ImageViewerDemo.axaml
@@ -9,7 +9,10 @@
     d:DesignWidth="800"
     mc:Ignorable="d">
     <UserControl.Resources>
-        <SolidColorBrush x:Key="MaskBackground" Opacity="0.2" Color="Red" />
+        <SolidColorBrush
+            x:Key="MaskBackground"
+            Opacity="0.2"
+            Color="Red" />
         <SolidColorBrush x:Key="MaskBorder" Color="Red" />
     </UserControl.Resources>
     <StackPanel>
@@ -20,7 +23,7 @@
         <u:ImageViewer
             Name="viewer"
             Width="600"
-            Height="300" 
+            Height="300"
             MinScale="0.5"
             Source="../Assets/3x.png">
             <u:ImageViewer.Overlayer>
@@ -117,6 +120,11 @@
                 Grid.Row="3"
                 Grid.Column="1"
                 Theme="{DynamicResource SimpleToggleSwitch}" />
+
+            <Button
+                Grid.Row="3"
+                Grid.Column="2" Click="Button_Click"
+                Content="测试设置为 null" />
         </Grid>
     </StackPanel>
 </UserControl>
diff --git a/demo/Ursa.Demo/Pages/ImageViewerDemo.axaml.cs b/demo/Ursa.Demo/Pages/ImageViewerDemo.axaml.cs
index e558339..2ddbb51 100644
--- a/demo/Ursa.Demo/Pages/ImageViewerDemo.axaml.cs
+++ b/demo/Ursa.Demo/Pages/ImageViewerDemo.axaml.cs
@@ -8,4 +8,19 @@ public partial class ImageViewerDemo : UserControl
     {
         InitializeComponent();
     }
+
+    Avalonia.Media.IImage? oldImg;
+
+    private void Button_Click(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
+    {
+        if(viewer.Source!=null)
+        {
+            oldImg = viewer.Source;
+            viewer.Source = null;
+        }
+        else
+        {
+            viewer.Source = oldImg;
+        }
+    }
 }
\ No newline at end of file
diff --git a/src/Ursa/Controls/ImageViewer/ImageViewer.cs b/src/Ursa/Controls/ImageViewer/ImageViewer.cs
index 021151f..6554adc 100644
--- a/src/Ursa/Controls/ImageViewer/ImageViewer.cs
+++ b/src/Ursa/Controls/ImageViewer/ImageViewer.cs
@@ -149,6 +149,10 @@ public class ImageViewer: TemplatedControl
     {
         if(!IsLoaded) return;
         IImage image = args.GetNewValue<IImage>();
+        if(image is null)
+        {
+            return;
+        }
         Size size = image.Size;
         double width = this.Bounds.Width;
         double height = this.Bounds.Height;