c# - 在 Autofac 中注册时如何避免使用 new 两次

Question

我想使用带参数的构造函数注册两个依赖项，但我只想在“依赖项”类上创建一次"new"。而不是这个:

builder.RegisterInstance(new ClassA(new Dependency())).As<IClassA>().SingleInstance();
builder.RegisterInstance(new ClassB(new Dependency())).AsSelf().SingleInstance();

我想要这样的东西:

Dependency dependency = new Dependency();
builder.RegisterInstance(new ClassA(dependency)).As<IClassA>().SingleInstance();
builder.RegisterInstance(new ClassB(dependency)).AsSelf().SingleInstance();

Answer 1

如果您先注册依赖项，它应该会在需要时自动传递给新实例。

假设:

public class ClassA : IClassA
{
    public ClassA(Dependency dependency)
    {
    }
 }

public class ClassB
{
    public ClassB(Dependency dependency)
    {
    }
 }

然后注册依赖

var dependency = new Dependency();
builder.RegisterInstance(dependency).As<Dependency>();
builder.RegisterType<ClassA>().As<IClassA>().SingleInstance();
builder.RegisterType<ClassB>().AsSelf().SingleInstance();