DotNET6 IOC自动注入

发表于 2022-07-05 本文字数 4.1k 字阅读时长 4 分钟

# 在开发过程中手动注入接口和实现很麻烦而且代码很冗余

# 所以需要整一个自动注入的方法解放双手

# 需要定义一个注入类型的枚举

	/// <summary>
	/// 注入类型
	/// </summary>
	public enum InjectType
	{
	// 作用域
	Scope,

	// 单例
	Single,

	// 瞬时
	Transient
	}

# 定义一个 Attribute

	[AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
	public class AutoInjectAttribute : Attribute
	{
	public AutoInjectAttribute(Type interfaceType, InjectType injectType)
	{
	Type = interfaceType;
	InjectType = injectType;
	}

	public Type Type { get; set; }

	/// <summary>
	/// 注入类型
	/// </summary>
	public InjectType InjectType { get; set; }
	}

# 自动依赖注入的方法

	/// <summary>
	/// 自动依赖注入
	/// </summary>
	public static class AutoInject
	{
	/// <summary>
	/// 自动注入所有的程序集有 InjectAttribute 标签
	/// </summary>
	/// <param name="serviceCollection"></param>
	/// <returns></returns>
	public static IServiceCollection AddAutoDi(this IServiceCollection serviceCollection)
	{
	var path = AppDomain.CurrentDomain.BaseDirectory;
	var assemblies = Directory.GetFiles(path, "*.dll").Select(Assembly.LoadFrom).ToList();
	foreach (var assembly in assemblies)
	{
	var types = assembly.GetTypes().Where(a => a.GetCustomAttribute<AutoInjectAttribute>() != null)
	.ToList();
	if (types.Count <= 0) continue;
	foreach (var type in types)
	{
	var attr = type.GetCustomAttribute<AutoInjectAttribute>();
	if (attr?.Type == null) continue;
	switch (attr.InjectType)
	{
	case InjectType.Scope:
	serviceCollection.AddScoped(attr.Type, type);
	break;
	case InjectType.Single:
	serviceCollection.AddSingleton(attr.Type, type);
	break;
	case InjectType.Transient:
	serviceCollection.AddTransient(attr.Type, type);
	break;
	default:
	throw new ArgumentOutOfRangeException();
	}
	}
	}

	return serviceCollection;
	}
	}

# 实现层和接口层

	/// <summary>
	/// 实现层调用特性
	/// </summary>
	[AutoInject(typeof(IHomeDataService), InjectType.Scope)]
	public class HomeDataService: IHomeDataService
	{
	public string GetUser()
	{
	return "张三";
	}
	}

	/// <summary>
	/// 接口层不需要做任何处理
	/// </summary>
	public interface IHomeDataService
	{
	string GetUser();
	}

# Program 注册到服务

	var builder = WebApplication.CreateBuilder(args);
	// 自动注入
	builder.Services.AddAutoDi();

# 即可完成自动注入

# 第二种方法扩展性更高，先定义三个接口对应三个生命周期

	/// <summary>
	/// 单例
	/// </summary>
	public interface ISingleton
	{
	}

	/// <summary>
	/// 瞬时
	/// </summary>
	public interface ITransient
	{
	}

	/// <summary>
	/// 作用域
	/// </summary>
	public interface IScoped
	{
	}

# 自动注入的方法

	public static IServiceCollection AddDataService(this IServiceCollection services)
	{
	var singletonType = typeof(ISingleton); // 单例
	var transientType = typeof(ITransient); // 瞬时
	var scopedType = typeof(IScoped); // 作用域
	// 获取实现了三个生命周期接口的程序集
	var allTypes = AppDomain.CurrentDomain.GetAssemblies()
	.SelectMany(a => a.GetTypes().Where(t =>
	t.GetInterfaces().Contains(transientType) \|\|
	t.GetInterfaces().Contains(singletonType)\|\|
	t.GetInterfaces().Contains(scopedType)));
	//class 的程序集
	var implementTypes = allTypes.Where(x => x.IsClass).ToArray();
	// 接口的程序集
	var interfaceTypes = allTypes.Where(x => x.IsInterface).ToArray();
	foreach (var implementType in implementTypes)
	{
	var interfaceType = interfaceTypes.FirstOrDefault(x => x.IsAssignableFrom(implementType));
	//class 有接口，用接口注入
	if (interfaceType != null)
	{
	// 判断用什么方式注入
	if (interfaceType.GetInterfaces().Contains(singletonType))
	{
	// 单例
	services.AddSingleton(interfaceType, implementType);
	}
	else if (interfaceType.GetInterfaces().Contains(transientType))
	{
	// 瞬时
	services.AddTransient(interfaceType, implementType);
	}
	else if(interfaceType.GetInterfaces().Contains(scopedType))
	{
	// 作用域
	services.AddScoped(interfaceType, implementType);
	}
	}
	else //class 没有接口，直接注入 class
	{
	// 判断用什么方式注入
	if (implementType.GetInterfaces().Contains(singletonType))
	{
	// 单例
	services.AddSingleton(implementType);
	}
	else if(implementType.GetInterfaces().Contains(transientType))
	{
	// 瞬时
	services.AddTransient(implementType);
	}
	else if (implementType.GetInterfaces().Contains(scopedType))
	{
	// 作用域
	services.AddScoped(implementType);
	}
	}
	}
	return services;
	}

# Program 注册服务

	// 自动注入
	builder.Services.AddDataService();

# 使用方法：在需要使用的接口继承对应生命周期的接口即可

	/// <summary>
	/// 实现层不做处理
	/// </summary>
	public class HomeDataService: IHomeDataService
	{
	public string GetUser()
	{
	return "张三";
	}
	}

	/// <summary>
	/// 接口层继承生命周期接口
	/// </summary>
	public interface IHomeDataService: ISingleton
	{
	string GetUser();
	}

技术