Shutdown COM error handler

Author: govert

Source/ExcelDna.IntelliSense.Host/ExcelDna.IntelliSense.Host.csproj

@@ -60,6 +60,9 @@
     </Content>
   </ItemGroup>
   <ItemGroup>
+    <None Include="ExcelDna.IntelliSense.Host-AddIn.xll.config">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     <None Include="packages.config" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />

Source/ExcelDna.IntelliSense/IntelliSenseProvider.cs

@@ -483,9 +483,20 @@ void OnInvalidate()
         public void Dispose()
         {
             Logger.Provider.Info("WorkbookIntelliSenseProvider.Dispose");
-            var xlApp = (Application)ExcelDnaUtil.Application;
-            xlApp.WorkbookOpen -= Excel_WorkbookOpen;
-            xlApp.WorkbookBeforeClose -= Excel_WorkbookBeforeClose;
+            try
+            {
+                var xlApp = (Application)ExcelDnaUtil.Application;
+                // might fail, e.g. if the process is exiting
+                if (xlApp != null)
+                {
+                    xlApp.WorkbookOpen -= Excel_WorkbookOpen;
+                    xlApp.WorkbookBeforeClose -= Excel_WorkbookBeforeClose;
+                }
+            }
+            catch (Exception ex)
+            {
+                Logger.Provider.Verbose($"WorkbookIntelliSenseProvider.Dispose Error {ex}");
+            }
         }
     }
 

Source/ExcelDna.IntelliSense/LoaderNotification.cs

@@ -101,6 +101,7 @@ void Notification(Reason notificationReason, IntPtr pNotificationData, IntPtr co
         }
 
         #region IDisposable Support
+        // CONSIDER: We might not need the finalizer support ...
         private bool disposedValue = false; // To detect redundant calls
 
         protected virtual void Dispose(bool disposing)