AutoFac-如何使用參數注冊和解析對象？

Question

public class FooController : ApiController
{
   private IDb db;
    public FooController (IDb context)
    {
        db = context;
    }

    public void DoSomething(string value)
    {
        var output = new DoSomethingElse(value);
    }
}

該類中的幾個方法都使用DoSomethingElse對象，但並非所有方法都必需。 如何注冊和解決DoSomethingElse ？

Answer 1

據我了解的問題：

public class FooController : ApiController
{
   private IDb db;
    public FooController (IDb context)
    {
        db = context;
    }

    public void DoSomething(string value)
    {
        var output = new DoSomethingElse(value);
    }
}

您不想每次實例化FooController都實例化DoSomethingElse類型。 您還希望在運行時為其提供一個值。

因此，這需要工廠模式：

public interface IDoSomethingElseFactory
{
    IDoSomethingElse Create(string value);
}

public class DoSomethingElseFactory : IDoSomethingElseFactory
{
    public IDoSomethingElse Create(string value)
    {
        // Every call to this method will create a new instance
        return new DoSomethingElse(value);
    }
}

public class FooController : ApiController
{
    private IDb db;
    private readonly IDoSomethingElseFactory doSomethingElseFactory;

    public FooController (
        IDb context,
        IDoSomethingElseFactory doSomethingElseFactory)
    {
        db = context;
        this.doSomethingElseFactory = doSomethingElseFactory;
    }

    public void DoSomething(string value)
    {
        // this will be the point at which a brand new
        // instance of `DoSomethingElse` will be created.
        var output = doSomethingElseFactory.Create(value);
    }
}

然后注冊：

builder.RegisterType<DoSomethingElseFactory>()
       .As<IDoSomethingElseFactory>()