correctly handle file save errors

src/modules/registrypreview/RegistryPreviewUILib/RegistryPreviewMainPage.Events.cs

@@ -107,7 +107,12 @@ private async void OpenButton_Click(object sender, RoutedEventArgs e)
                 {
                     case ContentDialogResult.Primary:
                         // Save, then continue the file open
-                        SaveFile();
+                        bool success = SaveFile();
+                        if (!success)
+                        {
+                            return;
+                        }
+
                         break;
                     case ContentDialogResult.Secondary:
                         // Don't save and continue the file open!
@@ -176,7 +181,7 @@ private void SaveButton_Click(object sender, RoutedEventArgs e)
             }
 
             // save and update window title
-            SaveFile();
+            _ = SaveFile();
             _updateWindowTitleFunction(_appFileName);
         }
 
@@ -200,7 +205,7 @@ private async void SaveAsButton_Click(object sender, RoutedEventArgs e)
             }
 
             _appFileName = filename;
-            SaveFile();
+            _ = SaveFile();
             UpdateToolBarAndUI(await OpenRegistryFile(_appFileName));
         }
 
@@ -281,7 +286,12 @@ private async void WriteButton_Click(object sender, RoutedEventArgs e)
                 {
                     case ContentDialogResult.Primary:
                         // Save, then continue the file open
-                        SaveFile();
+                        bool success = SaveFile();
+                        if (!success)
+                        {
+                            return;
+                        }
+
                         break;
                     case ContentDialogResult.Secondary:
                         // Don't save and continue the file open!

src/modules/registrypreview/RegistryPreviewUILib/RegistryPreviewMainPage.Utilities.cs

@@ -876,8 +876,8 @@ private bool DirtyCloseSaveFile()
                 _appFileName = filename;
             }
 
-            SaveFile();
-            return true;
+            bool r = SaveFile();
+            return r;
         }
 
         /// <summary>
@@ -959,8 +959,10 @@ public void UpdateUnsavedFileIndicator(bool show)
         /// <summary>
         /// Wrapper method that saves the current file in place, using the current text in editor.
         /// </summary>
-        private void SaveFile()
+        private bool SaveFile()
         {
+            bool saveSuccess = true;
+
             ChangeCursor(gridPreview, true);
 
             // set up the FileStream for all writing
@@ -989,6 +991,8 @@ private void SaveFile()
             }
             catch (UnauthorizedAccessException ex)
             {
+                saveSuccess = false;
+
                 // this exception is thrown if the file is there but marked as read only
                 ShowMessageBox(
                     resourceLoader.GetString("ErrorDialogTitle"),
@@ -997,6 +1001,8 @@ private void SaveFile()
             }
             catch
             {
+                saveSuccess = false;
+
                 // this catch handles all other exceptions thrown when trying to write the file out
                 ShowMessageBox(
                     resourceLoader.GetString("ErrorDialogTitle"),
@@ -1014,6 +1020,8 @@ private void SaveFile()
 
             // restore the cursor
             ChangeCursor(gridPreview, false);
+
+            return saveSuccess;
         }
 
         /// <summary>