Show error nicely when setting wallpaper fails

Author: t1m0thyj

scripts/installer.iss

@@ -50,6 +50,7 @@ Name: "finnish"; MessagesFile: "compiler:Languages\Finnish.isl"
 Name: "french"; MessagesFile: "compiler:Languages\French.isl"
 Name: "german"; MessagesFile: "compiler:Languages\German.isl"
 Name: "hebrew"; MessagesFile: "compiler:Languages\Hebrew.isl"
+Name: "hungarian"; MessagesFile: "compiler:Languages\Hungarian.isl"
 Name: "icelandic"; MessagesFile: "compiler:Languages\Icelandic.isl"
 Name: "italian"; MessagesFile: "compiler:Languages\Italian.isl"
 Name: "japanese"; MessagesFile: "compiler:Languages\Japanese.isl"

src/EventScheduler.cs

@@ -174,16 +174,26 @@ private void HandleDisplayEvent(DisplayEvent e)
                 }
             }
 
-            LoggingHandler.LogMessage("Setting wallpaper to {0}", imagePath);
-            if (e.displayIndex != DisplayEvent.LockScreenIndex)
+            LoggingHandler.LogMessage("Setting wallpaper to {0}@{1}", imagePath, e.displayIndex);
+            try
             {
-                UwpDesktop.GetHelper().SetWallpaper(imagePath, e.displayIndex);
+                if (e.displayIndex != DisplayEvent.LockScreenIndex)
+                {
+                    UwpDesktop.GetHelper().SetWallpaper(imagePath, e.displayIndex);
+                }
+                else
+                {
+                    UwpDesktop.GetHelper().SetLockScreen(imagePath);
+                }
+                e.lastImagePath = imagePath;
             }
-            else
+            catch (Exception exc)
             {
-                UwpDesktop.GetHelper().SetLockScreen(imagePath);
+                LoggingHandler.LogMessage("Error setting wallpaper: {0}", exc.ToString());
+                MessageDialog.ShowWarning(string.Format(Localization.GetTranslation(
+                    "Error occurred when setting wallpaper '{0}':\n\n{1}"),
+                    Path.GetRelativePath(Environment.CurrentDirectory, imagePath), exc.ToString()));
             }
-            e.lastImagePath = imagePath;
         }
 
         private void StartTimer(DateTime futureTime)

src/ThemeDialog.cs

@@ -394,7 +394,8 @@ private void ThemeDialog_Load(object sender, EventArgs e)
                 themeId => themeId != null) ?? -1;
             displayComboBox.SelectedIndex = activeThemeIndex != -1 ? activeThemeIndex : 0;
 
-            string activeTheme = JsonConfig.settings.activeThemes?[displayComboBox.SelectedIndex];
+            string activeTheme = JsonConfig.IsNullOrEmpty(JsonConfig.settings.activeThemes) ? null :
+                JsonConfig.settings.activeThemes[displayComboBox.SelectedIndex];
             string focusTheme = activeTheme ?? "";
             if (activeTheme == null && JsonConfig.firstRun)
             {