DependencyResolver 不解决依赖关系。为什么？

Question

我在一个项目中使用 Unity 作为我的 IoC。

UnityConfig 是这样设置的...

public static class UnityConfig
{
    private static readonly IUnityContainer container = new UnityContainer();

    public static void ConfigureIoCContainer()
    {
        My.Composition.Builder.Compose(container);

        DependencyResolver.SetResolver(new UnityDependencyResolver(container));
    }

    /// <summary>
    /// Gets the configured Unity container.
    /// </summary>
    public static IUnityContainer GetConfiguredContainer()
    {
        return container;
    }
}

My.Composition.Builder.Compose() 这样做...

    public static void Compose(IUnityContainer container)
    {
        var types = new List<Type>();

        types.AddRange(Services.Interface.Builder.GetTypes(container));
        types.AddRange(Services.Builder.GetTypes(container));            
        // ... lots more assemblies referenced here

        var distinctTypes = types.Distinct();

        container.RegisterTypes(distinctTypes, WithMappings.FromMatchingInterface, WithName.Default, WithLifetime.PerResolve);
    }

现在，在上面引用的 2 个程序集中，我 return 3 种类型； IConfigUow、ISecurityUow 和 IResourceUow 来自第一个，ConfigUow、SecurityUow 和 ResourceUow 来自第二个。

如果我在 UnityConfig 中调用 My.Composition.Builder.Compose(container) 之后的行放置一个断点并查看已注册类型的列表，我可以看到我应该看到的所有内容...

{Microsoft.Practices.Unity.ContainerRegistration}
    LifetimeManager: {Microsoft.Practices.Unity.PerResolveLifetimeManager}
    LifetimeManagerType: {Name = "PerResolveLifetimeManager" FullName = "Microsoft.Practices.Unity.PerResolveLifetimeManager"}
    MappedToType: {Name = "ConfigUow" FullName = "My.Services.Security.ConfigUow"}
    Name: null
    RegisteredType: {Name = "IConfigUow" FullName = "My.Services.Interface.Security.IConfigUow"}

{Microsoft.Practices.Unity.ContainerRegistration}
    LifetimeManager: {Microsoft.Practices.Unity.PerResolveLifetimeManager}
    LifetimeManagerType: {Name = "PerResolveLifetimeManager" FullName = "Microsoft.Practices.Unity.PerResolveLifetimeManager"}
    MappedToType: {Name = "SecurityUow" FullName = "My.Services.Security.SecurityUow"}
    Name: null
    RegisteredType: {Name = "ISecurityUow" FullName = "My.Services.Interface.Security.ISecurityUow"}

{Microsoft.Practices.Unity.ContainerRegistration}
    LifetimeManager: {Microsoft.Practices.Unity.PerResolveLifetimeManager}
    LifetimeManagerType: {Name = "PerResolveLifetimeManager" FullName = "Microsoft.Practices.Unity.PerResolveLifetimeManager"}
    MappedToType: {Name = "ResourceUow" FullName = "My.Services.Localization.ResourceUow"}
    Name: null
    RegisteredType: {Name = "IResourceUow" FullName = "My.Services.Interface.Localization.IResourceUow"}

但是，如果我让下一行执行以设置 DependencyResolver 并调用

DependencyResolver.Current.GetService<IConfigUow>();

null 的值是 returned。调用

DependencyResolver.Current.GetService<ISecurityUow>();

有效并且 return 是 SecurityUow 的实例。尝试解析 IResourceUow 也失败了。

我这辈子都看不出自己做错了什么。有人有什么想法吗？

更新

好的，所以通过调用 container.Resolve(IConfigUow) 我得到了一个被 DependencyResolver 屏蔽的异常。

错误表明我缺少类型映射。 ConfigUow 的构造函数如下所示...

    public ConfigUow(ICrudRepo<AM.Configuration> crudRepo = null) : base(crudRepo)
    {
        CrudRepo = crudRepo ?? DependencyResolver.Current.GetService<IConfigRepo>();
        Ctx = CrudRepo.GetContext();
    }

我不知道我需要为使用泛型的类型显式调用 RegisterType()。

所以，我需要做的就是像这样注册合适的类型...

container.RegisterType(typeof (ICrudRepo<>), typeof (CrudRepo<>));

一切都成功了。

对于未来的读者，这些页面证明是有帮助的...

Registering Generic Parameters and Types (MSDN)
Using Unity, how do you register type mappings for generics? (Whosebug)

Answer 1

答案是 DependencyResolver 掩盖了 IoC 容器抛出异常的事实。

发现解决问题并不难。邀请读者查看原始问题的 UPDATE 以了解我必须修复的内容以及我是如何修复的。

DependencyResolver 不解决依赖关系。为什么？

DependencyResolver doesn't Resolve dependencies. Why?

c#

dependency-injection

inversion-of-control

unity-container