PocoEmit.ServiceProvider 0.8.1.3-alpha

Emit映射集成IOC服务

一、注入IOC容器

• 注入IOC容器需要安装nuget包PocoEmit.ServiceProvider

1. 包含IOC容器的实体

class UserWithServiceProvider
{
    public int Id { get; set; }
    public string Name { get; set; }
    public IServiceProvider ServiceProvider { get; set; }
}

2. 注册、转化并注入的代码

• UseSingleton是把容器作为唯一容器注入
• UseScope是使用当前Scope的子容器
• UseContext是在Mvc下,使用当前HttpContext的RequestServices子容器

var services = new ServiceCollection();
var serviceProvider = services.BuildServiceProvider();
var mapper = Mapper.Create();
mapper.UseSingleton(serviceProvider);
var dto = new UserDTO { Id = 1, Name = "Jxj" };
UserWithServiceProvider user = mapper.Convert<UserDTO, UserWithServiceProvider>(dto);
Assert.NotNull(user.ServiceProvider);

二、当然还可以注入容器内的服务

1. UserDomain多出来的UserDomain需要注入

• 这次我们用IOC来管理UserRepository
• 这样才能更好的利用依赖注入
• UserRepository可能还会依赖其他的
• 手动维护对象可能会很麻烦,IOC容器擅长维护这些复杂关系

    class UserDomain(UserRepository repository, int id, string name)
    {
        private readonly UserRepository _repository = repository;
        public UserRepository Repository
            => _repository;
        public int Id { get; } = id;
        public string Name { get; } = name;
        // ...
    }
    class UserRepository
    {
        void Add(UserDomain user) { }
        void Update(UserDomain entity) { }
        void Remove(UserDomain entity) { }
    }

2. 注册、转化并注入的代码

• 通过UseScope注入IOC容器
• 通过UseDefault告知这个类型从IOC容器中注入

var services = new ServiceCollection()
    .AddScoped<UserRepository>();
var serviceProvider = services.BuildServiceProvider();
var mapper = Mapper.Create();
mapper.UseScope(serviceProvider)
     .UseDefault<UserRepository>();
var dto = new UserDTO { Id = 1, Name = "Jxj" };
UserDomain user = mapper.Convert<UserDTO, UserDomain>(dto);
Assert.NotNull(user.Repository);

三、支持IOC容器的特性

• 支持FromKeyedServices
• 支持FromServices

1. FromKeyedServices标记注入点和服务键

class UserDomain1([FromKeyedServices("User1")]UserRepository repository, int id, string name)
    : UserDomain(repository, id, name)
{
}
class UserDomain2([FromKeyedServices("User2")] UserRepository repository, int id, string name)
    : UserDomain(repository, id, name)
{
}
class UserDomain(UserRepository repository, int id, string name)
{
    private readonly UserRepository _repository = repository;
    public UserRepository Repository
        => _repository;
    public int Id { get; } = id;
    public string Name { get; } = name;
    // ...
}
class UserRepository(string tableName)
{
    private readonly string _tableName = tableName;
    public string TableName 
        => _tableName;
    void Add(UserDomain user) { }
    void Update(UserDomain entity) { }
    void Remove(UserDomain entity) { }
}

2. 注册、转化并注入的代码

• 由于识别出FromKeyedServices,就不需要UseDefault
• 这样简洁由优雅

string table1 = "User1";
string table2 = "User2";
var services = new ServiceCollection()
    .AddKeyedScoped(table1, (_, _) => new UserRepository(table1))
    .AddKeyedScoped(table2, (_, _) => new UserRepository(table2));
var serviceProvider = services.BuildServiceProvider();
var mapper = Mapper.Create();
mapper.UseScope(serviceProvider);
var dto = new UserDTO { Id = 1, Name = "Jxj" };
UserDomain user = mapper.Convert<UserDTO, UserDomain1>(dto);
Assert.NotNull(user.Repository);
UserDomain user2 = mapper.Convert<UserDTO, UserDomain2>(dto);
Assert.NotNull(user2.Repository);