dependency-injection - 防止解析未注册的类

Question

Unity 会解析类，即使它们没有在容器中注册。是否可以更改容器配置，以便应显式注册类才能解析？

Answer 1

您可以创建自定义构建器策略并检查类型是否已在容器中注册:

class Program
{
    static void Main(string[] args)
    {
        var container = new UnityContainer();
        container.AddNewExtension<FactoryUnityExtension>();

        try
        {
            container.Resolve<Program>();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

        container.RegisterType<Program>();

        var v = container.Resolve<Program>();
        Console.WriteLine(v);
    }
}


public class CustomFactoryBuildStrategy : BuilderStrategy
{
    private ExtensionContext baseContext;

    public CustomFactoryBuildStrategy(ExtensionContext baseContext)
    {
        this.baseContext = baseContext;
    }

    public override void PreBuildUp(IBuilderContext context)
    {
        var key = (NamedTypeBuildKey)context.OriginalBuildKey;

        if (baseContext.Container.Registrations.All(o => o.RegisteredType != key.Type))
        {
            throw new InvalidOperationException();
        }
    }
}

public class FactoryUnityExtension : UnityContainerExtension
{
    private CustomFactoryBuildStrategy strategy;
    protected override void Initialize()
    {
        this.strategy = new CustomFactoryBuildStrategy(Context);
        Context.Strategies.Add(strategy, UnityBuildStage.PreCreation);
    }
}