Viewer: Fixed bug where game over message is displayed more than once

jonthysell · Aug 23, 2021 · 253a635 · 253a635
1 parent 3ceb59e
commit 253a635
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Showing 2 changed files with 16 additions and 4 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## next ##
 
 * Engine: Fixed bug where pondering starts after a game is over, causing an error
+* Viewer: Fixed bug where game over message is displayed more than once
 * Viewer: Update Avalonia to 0.10.7
 
 ## v0.11.3 ##

diff --git a/src/Mzinga.Viewer/MessageHandlers.cs b/src/Mzinga.Viewer/MessageHandlers.cs
@@ -60,6 +60,8 @@ private static async Task ShowExceptionAsync(ExceptionMessage message)
         {
             try
             {
+                Trace.TraceInformation($"ShowExceptionAsync: { message.ExceptionVM.Exception }");
+
                 InformationWindow window = new InformationWindow
                 {
                     VM = message.ExceptionVM,
@@ -73,16 +75,25 @@ private static async Task ShowExceptionAsync(ExceptionMessage message)
             }
         }
 
+        // Code dispatched to Avalonia's UI thread sometimes runs multiple times, which causes us to display multiple game over messages
+        private static volatile InformationWindow _currentInformationWindow = null;
+
         private static async Task ShowInformationAsync(InformationMessage message)
         {
             try
             {
-                InformationWindow window = new InformationWindow
+                Trace.TraceInformation($"ShowInformationAsync: { message.InformationVM.Message }");
+
+                if (_currentInformationWindow is null)
                 {
-                   VM = message.InformationVM,
-                };
+                    _currentInformationWindow = new InformationWindow
+                    {
+                        VM = message.InformationVM,
+                    };
 
-                await window.ShowDialog(MainWindow);
+                    await _currentInformationWindow.ShowDialog(MainWindow);
+                    _currentInformationWindow = null;
+                }
             }
             catch (Exception ex)
             {