添加项目文件。

Core/MAX.Core/Infrastructure/IStartup.cs

@@ -0,0 +1,18 @@
+using MAX.Core.DependencyInjection;
+
+namespace MAX.Core.Infrastructure;
+
+/// <summary>
+/// 启动器：实现 <see cref="IDependencyRegistrar"/>，由宿主项目统一发现并按 <see cref="Priority"/> 排序执行。
+/// </summary>
+public interface IStartup : IDependencyRegistrar
+{
+	/// <summary>
+	/// 优先级（优先级越高越先执行）
+	/// </summary>
+	int Priority { get; }
+	/// <summary>
+	/// 初始化
+	/// </summary>
+	void Initialize();
+}

Core/MAX.Core/Infrastructure/SingleInstance.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Reflection;
+
+namespace MAX.Core.Infrastructure;
+
+/// <summary>
+/// 单例，需要在当前类中定义
+/// </summary>
+/// <typeparam name="T"></typeparam>
+public class SingleInstance<T> where T : class
+{
+	private static readonly object lockObj = new();
+	private static T mySelf;//= default(T);
+	public static T Instance
+	{
+		get
+		{
+			lock (lockObj)
+			{
+				mySelf ??= InstanceCreator.CreateInstance<T>();
+			}
+
+			return mySelf;
+		}
+	}
+}
+
+public static class InstanceCreator
+{
+	public static T CreateInstance<T>()
+	{
+		Type type = typeof(T);
+		try
+		{
+			return (T)type.Assembly.CreateInstance(type.FullName, true, BindingFlags.NonPublic | BindingFlags.Instance, null, null, null, null);
+		}
+		catch (MissingMethodException ex)
+		{
+			throw new Exception($"{ex.Message}\n(单例模式下，构造函数必须为 private)");
+		}
+	}
+}