feat: implement locale switch.

src/Ursa.Themes.Semi/Index.axaml.cs

@@ -0,0 +1,55 @@
+using System.Globalization;
+using System.Runtime.CompilerServices;
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+using Avalonia.Markup.Xaml.Styling;
+using Avalonia.Platform;
+using Avalonia.Styling;
+
+namespace Ursa.Themes.Semi;
+
+public class SemiTheme: Styles
+{
+    private static readonly Dictionary<CultureInfo, string> _localeToResource = new()
+    {
+        { new CultureInfo("zh-CN"), "avares://Ursa.Themes.Semi/Locale/zh-CN.axaml" },
+        { new CultureInfo("en-US"), "avares://Ursa.Themes.Semi/Locale/en-US.axaml" },
+    };
+    
+    private readonly IServiceProvider? sp;
+    public SemiTheme(IServiceProvider? provider = null)
+    {
+        AvaloniaXamlLoader.Load(provider, this);
+    }
+
+    private CultureInfo? _locale;
+    public CultureInfo? Locale
+    {
+        get => _locale;
+        set
+        { 
+            _locale = value;
+            var resource = TryGetLocaleResource(value);
+            var d = AvaloniaXamlLoader.Load(sp, new Uri(resource)) as ResourceDictionary;
+            foreach (var kv in d)
+            {
+                this.Resources.Add(kv);
+            }
+        }
+    }
+    
+    private string TryGetLocaleResource(CultureInfo? locale)
+    {
+        if (locale is null)
+        {
+            return _localeToResource[new CultureInfo("zh-CN")];
+        }
+
+        if (_localeToResource.TryGetValue(locale, out var resource))
+        {
+            return resource;
+        }
+        return _localeToResource[new CultureInfo("zh-CN")];
+    }
+}