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我正在使用提供者模式和 Unity。

这是典型的提供者实现。我有SomeProvider作为抽象基础提供者的抽象方法以及实例化defaultProvider.

public abstract class SomeProvider : ProviderBase
{
    #region provider boilerplate

    private const string PROVIDER_NAME = "someProvider";
    private static volatile SomeProvider defaultProvider = null;
    public static SomeProvider Provider
    {
        get { return defaultProvider; }
    }
    private static object providerLockObject = new object();
    static SomeProvider()
    {
        LoadProvider();
    }
    private static void LoadProvider()
    {
        if (defaultProvider == null)
        {
            lock (providerLockObject)
            {
                if (defaultProvider == null)
                {
                    // exception handling omitted for brevity
                    var section = ConfigurationManager.GetSection(PROVIDER_NAME)
                        as BaseProviderConfigurationSection;
                    defaultProvider = ProvidersHelper.InstantiateProvider(
                        section.Providers[section.DefaultProvider], typeof(SomeProvider)) as SomeProvider;
                }
            }
        }
    }

    protected SomeProvider() { }

    #endregion

    #region abstract methods

    public abstract bool DoSomething();

    #endregion
}

这是ASomeProvider实现的SomeProvider。请注意，ASomeProvider具有依赖性ADependency但SomeProvider没有。

public class ASomeProvider : SomeProvider
{
    #region provider boilerplate

    private string name;
    public override string Name
    {
        get { return name; }
    }

    public override void Initialize(string name, NameValueCollection config)
    {
        this.name = name;
        base.Initialize(name, config);
    }

    #endregion

    // Provider pattern needs parameterless ctor and calls this
    public ASomeProvider() { }
    // constructor injection
    public ASomeProvider(ADependency aDependency)
    {
        this.ADependency = aDependency;
    }

    [Dependency]
    public SomeDependency ADependency { get; set; }

    #region methods

    public override void DoSomething()
    {
        // do something
    }

    #endregion
}

class SomeDependency {}

我ASomeProvider在业务层中使用如下：

public class SomeBusinessLayer
{
    public SomeProvider someProvider;

    public SomeBusinessLayer(SomeProvider someProvider)
    {
        this.someProvider = someProvider;
    }

    #region methods
    public bool DoSomethingWrapper()
    {
        return someProvider.DoSomething();
    }
    #endregion
}

我有BusinessLayerFactory使用 Unity 连接对象并返回对象的工厂，如下所示：

public static class BusinessLayerFactory
{
    private static UnityContainer container;

    private static void WireUp()
    {
        container = new UnityContainer();

        container.RegisterInstance(SomeProvider.Provider);
        container.RegisterInstance(new SomeDependency());
        container.RegisterType<SomeBusinessLayer>(new ContainerControlledLifetimeManager());
    }
    public static SomeBusinessLayer SomeBusinessLayer_Unity
    {
        get
        {
            return container.Resolve<SomeBusinessLayer>();
        }
    }
    public static SomeBusinessLayer SomeBusinessLayer_Self()
    {
        var asomeProvider = SomeProvider.Provider as ASomeProvider;
        if (asomeProvider != null && asomeProvider.ADependency == null)
            asomeProvider.ADependency = new ADependency();
        return new SomeBusinessLayer(SomeProvider.Provider);
    }
}

我遇到的问题是，当我解决 get 时SomeBusinessLayer，someProvider它的依赖项ADependency为 null。

var someBusinessLayer = BusinessLayerFactory.SomeBusinessLayer_Unity;

((ASomeProvider)someBusinessLayer.someProvider).ADependency是null。

原因是提供者模式使用辅助方法ProvidersHelper.InstantiateProvider(ProviderSettings providerSettings, Type type)来实例化默认提供者，而不是通过 Unity 的Resolve<T>()方法。

我可以考虑在没有 Unity 的情况下执行此操作，如我在SomeBusinessLayer_Selfwhere I new ADependencyif中所示，null但只是想知道 Unity 是否以及如何处理此问题。

方法注入或Ctor注入对我来说很好。

我该如何解决这个问题并让 Unity 和 Provider 模式一起工作？我使用 Unity 的主要原因是在工厂中连接对象。

我没有使用 MVC。

更新：

要解决此问题： . 给@seth-flowers的小费

如果没有明确的演员表，我想不出办法container.BuildUp<ASomeProvider>(aSomeProvider)。

container.RegisterInstance(new SomeDependency());

//this does not build up the object with dependency
container.BuildUp(SomeProvider.Provider);
//this works and does build up
var aSomeProvider = SomeProvider.Provider as ASomeProvider;
if(aSomeProvider != null)
    container.BuildUp<ASomeProvider>(aSomeProvider);
//compile error
container.BuildUp<ASomeProvider>(SomeProvider.Provider);

container.RegisterInstance(SomeProvider.Provider);

container.RegisterType<SomeBusinessService>(new ContainerControlledLifetimeManager());
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1 回答 1

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难道你不能在你的方法中使用UnityContainer.BuildUp来充实你的实例BusinessLayerFactory.WireUp的依赖关系吗？SomeProvider.Provider您的对象仍将通过您的提供者实现构建，但将通过统一进行依赖注入。

例如：

private static void WireUp()
{
    container = new UnityContainer();

    container.RegisterInstance(SomeProvider.Provider);
    container.RegisterInstance(new SomeDependency());
    container.RegisterType<SomeBusinessLayer>(
        new ContainerControlledLifetimeManager());

    container.BuildUp<ASomeProvider>(SomeProvider.Provider as ASomeProvider);
}

BuildUp的文档说明如下：

当您不控制实例的构造（例如，通过 XAML 创建的 ASP.NET 页面或对象）但仍希望执行属性和其他注入时，此方法很有用。

于 2012-10-31T18:01:56.517 回答