Autofac提供了ILifetimeScope接口，可以用于从容器中获取现有的LifetimeScope。可以通过在需要使用LifetimeScope的类中注入ILifetimeScope来实现该功能。以下是一个示例代码：

public class MyClass
{
    private readonly ILifetimeScope _lifetimeScope;

    public MyClass(ILifetimeScope lifetimeScope)
    {
        _lifetimeScope = lifetimeScope;
    }

    public void DoSomething()
    {
        // 使用_lifetimeScope进行操作
        using (var scope = _lifetimeScope.BeginLifetimeScope())
        {
            // 在子生命周期中执行操作
        }
    }
}

public class MainClass
{
    private readonly ILifetimeScope _lifetimeScope;

    public MainClass(ILifetimeScope lifetimeScope)
    {
        _lifetimeScope = lifetimeScope;
    }

    public void DoSomething()
    {
        // 使用_lifetimeScope进行操作
        using (var scope = _lifetimeScope.BeginLifetimeScope())
        {
            var myClass = scope.Resolve();
            myClass.DoSomething();
        }
    }
}

// 在注册依赖关系时，将ILifetimeScope添加为依赖项
var builder = new ContainerBuilder();
builder.RegisterType().AsSelf();
builder.RegisterType().AsSelf();
builder.Register(c => c.Resolve().Resolve()).As();
var container = builder.Build();

// 从容器中解析MainClass，并调用DoSomething方法
var mainClass = container.Resolve();
mainClass.DoSomething();

在上面的示例中，MainClass通过注入ILifetimeScope来获取现有的LifetimeScope，并在需要时使用它来解析和使用MyClass。这样可以避免在各处传递LifetimeScope的引用。