parse resource dictionaries [skip ci]

Author: ButchersBoy

MaterialDesignColors.WpfExample/MainWindow.xaml.cs

@@ -28,6 +28,10 @@ public MainWindow()
 
             new CardsWindow().Show();
             new ListsWindow().Show();
+            new PaletteSelectorWindow()
+            {
+                DataContext = new PaletteSelectorViewModel()
+            }.Show();
         }
 
 	    private void ToggleButton_OnChecked(object sender, RoutedEventArgs e)

MaterialDesignColors.WpfExample/PaletteSelectorViewModel.cs

@@ -3,10 +3,41 @@
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using System.Text.RegularExpressions;
+using System.Windows;
 
 namespace MaterialDesignColors.WpfExample
 {
     public class PaletteSelectorViewModel
     {
-    }
+        public PaletteSelectorViewModel()
+        {
+            AscertainCurrentResourceDictionaries();
+        }
+
+        private void AscertainCurrentResourceDictionaries()
+        {
+            var lightDarkResourceDictionary = Application.Current.Resources.MergedDictionaries
+                .Where(rd => rd.Source != null)
+                .SingleOrDefault(rd => Regex.Match(rd.Source.AbsolutePath, @"(\/MaterialDesignThemes.Wpf;component\/Themes\/MaterialDesignTheme\.)((Light)|(Dark))").Success);
+            if (lightDarkResourceDictionary == null)
+                throw new ApplicationException("Unable to find Light/Dark base theme in Application resources.");
+            var lightDarkDescription = Regex.Match(lightDarkResourceDictionary.Source.AbsolutePath, "(?'desc'(Light)|(Dark))(.xaml)$").Groups[
+                "desc"].Value;
+
+            ResourceDictionary primaryColorResourceDictionary;
+            if (!TryFindSwatchDictionary(Application.Current.Resources, "PrimaryHueMidBrush", out primaryColorResourceDictionary))
+                throw new ApplicationException("Unable to find primary color definition in Application resources.");
+
+            ResourceDictionary accentolorResourceDictionary;
+            if (!TryFindSwatchDictionary(Application.Current.Resources, "SecondaryAccentBrush", out accentolorResourceDictionary))
+                throw new ApplicationException("Unable to find accent color definition in Application resources.");
+        }
+
+        private bool TryFindSwatchDictionary(ResourceDictionary parentDictionary, string expectedBrushName, out ResourceDictionary dictionary)
+        {
+            dictionary = parentDictionary.MergedDictionaries.SingleOrDefault(rd => rd[expectedBrushName] != null);
+            return dictionary != null;
+        }
+    }    
 }