如何使用构造函数中的参数或任何条件实现 autofac 依赖注入？

Question

Before using any dependency injection 我正在使用简单的 interface 制作如下所示的 loosely coupled code -

Program.cs

class Program
    {
        static void Main(string[] args)
        {
            Customer obj = new Customer(new OracleData());
            obj.Add();
        }
    }

Customer.cs

 public class Customer
    {
        private Idata iobj;
        public Customer(Idata newiobj)
        {
            iobj = newiobj;
        }
        public void Add()
        {
            iobj.AddData();
        }
    }

OracleData.cs

 public class OracleData : Idata
    {
        public void AddData()
        {
            throw new NotImplementedException();
        }
    }

SQLData.cs

public class SQLData : Idata
{
    public void AddData()
    {
        throw new NotImplementedException();
    }
}

Idata.cs

 public interface Idata
    {
        void AddData();
    }

现在我尝试使用 Autofac DI 库 - 我想知道它总是最后注入的 class 对象，如何使用构造函数或任何条件设置解析对象？

代码使用 Autofac DI -

static void Main(string[] args)
        {

            var builder = new ContainerBuilder();
            builder.RegisterType<Customer>();
            builder.RegisterType<OracleData>().As<Idata>();
            builder.RegisterType<SQLData>().As<Idata>();
            var container = builder.Build();
            using (var scope = container.BeginLifetimeScope())
            {
                var app = scope.Resolve<Idata>();
                app.AddData();
            }

            //commented
            //Customer obj = new Customer(new OracleData());
            //obj.Add();
        }

Answer 1

如果您需要定义您将在入口点使用的实现，您可以这样做：

    static void Main(string[] args)
    {
        var builder = new ContainerBuilder();
        builder.RegisterType<Customer>();

        if(args[0] == "oracle")
            builder.RegisterType<OracleData>().As<Idata>();
        else
            builder.RegisterType<SQLData>().As<Idata>();

        var container = builder.Build();

        using (var scope = container.BeginLifetimeScope())
        {
            var app = scope.Resolve<Idata>();
            app.AddData();
        }

        //commented
        //Customer obj = new Customer(new OracleData());
        //obj.Add();
    }

如何使用构造函数中的参数或任何条件实现 autofac 依赖注入？

how to implement autofac dependency injection with parameter in constructor or with any condition?

c#

dependency-injection

ioc-container

inversion-of-control

autofac