更新

WPFDark/ThemeManager.cs

@@ -0,0 +1,106 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+
+using WPFDark.Properties;
+
+namespace WPFDark;
+public class ThemeManager
+{
+    private static ThemeManager? _themeManagerInstance;
+
+    private readonly Application? application;
+
+    //private Window? mainWindow;
+
+    private ResourceDictionary? resources;
+
+    internal static string LibraryNamespace => Assembly.GetExecutingAssembly().GetName().Name;
+
+    public static string ThemesDictionary => $"pack://application:,,,/{LibraryNamespace};component/Themes/Generic.xaml";
+    /// <summary>
+    /// 获取或设置应用程序的资源。
+    /// </summary>
+    public object TryFindResource(object resourceKey) { return Resources[resourceKey]; }
+    /// <summary>
+    /// 初始化 <see cref="ThemeManager"/> 实例.
+    /// </summary>
+    private ThemeManager(Application? application)
+    {
+        if (application is null)
+        {
+            return;
+        }
+
+        if (!ApplicationHasResources(application))
+        {
+            return;
+        }
+
+        this.application = application;
+
+        System.Diagnostics.Debug
+            .WriteLine($"INFO | {typeof(ThemeManager)} application is {this.application}", "WPFDark");
+    }
+    private static bool ApplicationHasResources(Application? application)
+    {
+        return application
+            .Resources.MergedDictionaries
+            .Where(e => e.Source is not null)
+            .Any(
+                e => e.Source
+                    .ToString()
+                    .Contains(LibraryNamespace));
+    }
+    /// <summary>
+    /// 获取当前UI应用程序。
+    /// </summary>
+    public static ThemeManager Current
+    {
+        get
+        {
+            _themeManagerInstance ??= new ThemeManager(Application.Current);
+
+            return _themeManagerInstance;
+        }
+    }
+    /// <summary>
+    /// 获取或设置应用程序的资源。
+    /// </summary>
+    public ResourceDictionary Resources
+    {
+        get
+        {
+            if (resources is null)
+            {
+                resources = [];
+
+                try
+                {
+                    var themesDictionary = new ThemesDictionary();
+                    var controlsDictionary = new ControlsDictionary();
+                    resources.MergedDictionaries.Add(themesDictionary);
+                    resources.MergedDictionaries.Add(controlsDictionary);
+                }
+                catch
+                {
+                }
+            }
+
+            return application?.Resources ?? resources;
+        }
+        set
+        {
+            if (application is not null)
+            {
+                application.Resources = value;
+            }
+
+            resources = value;
+        }
+    }
+}