RegistryUtils

Shared/MeloongCore.csproj

@@ -15,6 +15,7 @@
 	</PropertyGroup>
 
 	<ItemGroup>
+		<PackageReference Include="Microsoft.Win32.Registry" Version="5.0.0" />
 		<PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
 		<PackageReference Include="PolySharp" Version="1.15.0">
 			<PrivateAssets>all</PrivateAssets>

Shared/Utils/RegistryUtils.cs

@@ -0,0 +1,79 @@
+using Microsoft.Win32;
+namespace MeloongCore;
+
+public static class RegistryUtils {
+    /// <summary>在注册表中表示 <c>null</c> 的标记字符串。</summary>
+    public const string NULL_STRING = "__NULL__";
+
+    /// <summary>
+    /// 读取注册表键。
+    /// <para/>若键值为 <see cref="NULL_STRING"/>，则返回 <c>null</c>。
+    /// </summary>
+    public static (object? result, bool exists) Read(string keyPath) {
+        var (hive, subKeyPath, valueName) = ParsePath(keyPath);
+        using RegistryKey baseKey = RegistryKey.OpenBaseKey(hive, RegistryView.Default);
+        using RegistryKey? subKey = baseKey.OpenSubKey(subKeyPath);
+        var result = subKey?.GetValue(valueName);
+        if (result is null) return (null, false);
+        return (result is string str && str == NULL_STRING ? null : result, true);
+    }
+    /// <summary>
+    /// 读取注册表键，若该键不存在则返回 <paramref name="defaultValue"/>。
+    /// <para/>若键值为 <see cref="NULL_STRING"/>，则返回 <c>null</c>。
+    /// </summary>
+    public static object? ReadOrDefault(string keyPath, object? defaultValue) {
+        var (result, exists) = Read(keyPath);
+        return exists ? result : defaultValue;
+    }
+
+    /// <summary>
+    /// 写入注册表键。
+    /// <para/>会自动创建对应的子键。
+    /// <para/>若 <paramref name="value"/> 为 <c>null</c>，则写入 <see cref="NULL_STRING"/>。
+    /// </summary>
+    public static void Write(string keyPath, object? value) {
+        var (hive, subKeyPath, valueName) = ParsePath(keyPath);
+        using RegistryKey baseKey = RegistryKey.OpenBaseKey(hive, RegistryView.Default);
+        using RegistryKey subKey = baseKey.CreateSubKey(subKeyPath);
+        subKey.SetValue(valueName, value ?? NULL_STRING);
+    }
+
+    /// <summary>
+    /// 判断对应的注册表键是否存在。
+    /// </summary>
+    public static bool Has(string keyPath) {
+        var (hive, subKeyPath, valueName) = ParsePath(keyPath);
+        using RegistryKey baseKey = RegistryKey.OpenBaseKey(hive, RegistryView.Default);
+        using RegistryKey? subKey = baseKey.OpenSubKey(subKeyPath);
+        if (subKey is null) return false;
+        object notFound = new();
+        return !ReferenceEquals(subKey.GetValue(valueName, notFound), notFound);
+    }
+
+    /// <summary>
+    /// 删除注册表键。若不存在则不执行操作。
+    /// </summary>
+    public static void Delete(string keyPath) {
+        var (hive, subKeyPath, valueName) = ParsePath(keyPath);
+        using RegistryKey baseKey = RegistryKey.OpenBaseKey(hive, RegistryView.Default);
+        using RegistryKey? subKey = baseKey.OpenSubKey(subKeyPath, writable: true);
+        subKey?.DeleteValue(valueName, throwOnMissingValue: false);
+    }
+
+    private static (RegistryHive Hive, string SubKeyPath, string ValueName) ParsePath(string fullPath) {
+        int hiveEnd = fullPath.IndexOf('\\');
+        int valueStart = fullPath.LastIndexOf('\\');
+        if (hiveEnd <= 0 || hiveEnd > valueStart) throw new ArgumentException($"注册表路径不完整（{fullPath}）", nameof(fullPath));
+        RegistryHive hive = fullPath.Substring(0, hiveEnd).ToUpperInvariant() switch {
+            "HKEY_CLASSES_ROOT" => RegistryHive.ClassesRoot,
+            "HKEY_CURRENT_USER" => RegistryHive.CurrentUser,
+            "HKEY_LOCAL_MACHINE" => RegistryHive.LocalMachine,
+            "HKEY_USERS" => RegistryHive.Users,
+            "HKEY_CURRENT_CONFIG" => RegistryHive.CurrentConfig,
+            _ => throw new ArgumentException($"注册表路径有误（{fullPath}）", nameof(fullPath))
+        };
+        string subKeyPath = valueStart == hiveEnd ? "" : fullPath.Substring(hiveEnd + 1, valueStart - hiveEnd - 1);
+        return (hive, subKeyPath, fullPath.Substring(valueStart + 1));
+    }
+
+}