public static void ChangeTheme(ThemeEnum theme) { if (CurrentTheme == theme) { return; } ICollection <ResourceDictionary> mergedDictionaries = Application.Current.Resources.MergedDictionaries; if (mergedDictionaries != null) { mergedDictionaries.Clear(); switch (theme) { case ThemeEnum.Alternative: mergedDictionaries.Add(new AlternativeTheme()); break; case ThemeEnum.Default: default: mergedDictionaries.Add(new DefaultTheme()); break; } CurrentTheme = theme; Debug.WriteLine($"Changed theme to: {theme.ToString()}"); } }