C# System.Web.Mvc类型的Unity ResolutionFailedException

我的WebApp是WebForms页面和MVC4页面的组合

使用Unity，我得到以下异常

异常类型：

Microsoft.Practices.Unity.ResolutionFailedException, Microsoft.Practices.Unity, Version=2.1.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35

Resolution of the dependency failed, type = "System.Web.Mvc.ModelMetadataProvider", name = "(none)".  Exception occurred while: while resolving.  Exception is: InvalidOperationException - The type ModelMetadataProvider does not have an accessible constructor.  At the time of the exception, the container was:
Resolving System.Web.Mvc.ModelMetadataProvider,(none)

The type ModelMetadataProvider does not have an accessible constructor.

消息：

Microsoft.Practices.Unity.ResolutionFailedException, Microsoft.Practices.Unity, Version=2.1.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35

Resolution of the dependency failed, type = "System.Web.Mvc.ModelMetadataProvider", name = "(none)".  Exception occurred while: while resolving.  Exception is: InvalidOperationException - The type ModelMetadataProvider does not have an accessible constructor.  At the time of the exception, the container was:
Resolving System.Web.Mvc.ModelMetadataProvider,(none)

The type ModelMetadataProvider does not have an accessible constructor.

具有以下

内部异常

：

消息：

Microsoft.Practices.Unity.ResolutionFailedException, Microsoft.Practices.Unity, Version=2.1.505.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35

Resolution of the dependency failed, type = "System.Web.Mvc.ModelMetadataProvider", name = "(none)".  Exception occurred while: while resolving.  Exception is: InvalidOperationException - The type ModelMetadataProvider does not have an accessible constructor.  At the time of the exception, the container was:
Resolving System.Web.Mvc.ModelMetadataProvider,(none)

The type ModelMetadataProvider does not have an accessible constructor.

堆栈跟踪：

at Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.ThrowForNullExistingObje ct(IBuilderContext context)  
at BuildUp_System.Web.Mvc.ModelMetadataProvider(IBuilderContext )  
at Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context)  
at Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context)  
at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context)  
at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object existing, String name, IEnumerable`1 resolverOverrides)  

对于以下类型，我始终获得相同的分辨率异常：

System.Web.Mvc.ITempDataProvide  
System.Web.Mvc.Async.IAsyncActionInvoker  
System.Web.Mvc.IActionInvoker  
System.Web.Mvc.ModelMetadataProvider  
System.Web.Mvc.IViewPageActivator

在应用程序启动中，我将通过以下方式建立国际奥委会：

DependencyResolver.SetResolver(new UnityDependencyResolver(UnityConfigurator.GetContainer()));

…其中

GetContainer

返回所有注册的类型和

unitydependencysolver

is-a

idependencysolver

你知道是什么导致了这个问题吗

谢谢，

---

--Ed

我不确定UnityConfigurator.GetContainer（）返回的容器实例如何准确运行，但我假设它会在需要时尝试单独解析

ModelMetadataProvider

。此

modelmataprovider

具有一些容器不知道的依赖项，只有初始MVC解析器才能解析这些依赖项。“初始MVC解析器”是指调用

DependencyResolver.SetResolver（…）

之前的

DependencyResolver.Current

的结果。 因此，您需要在自己的容器上实现代理，并将初始MVC解析器用作回退

代理的实现应该是什么样子的一个快速示例：

public class MvcDependencyResolver:System.Web.Mvc.IDependencyResolver
{
    private readonly IDependencyResolver _resolver;

    private readonly System.Web.Mvc.IDependencyResolver _fallbackResolver;

    public MvcDependencyResolver(IDependencyResolver resolver, System.Web.Mvc.IDependencyResolver fallbackResolver)
    {
        this._resolver = resolver;
        this._fallbackResolver = fallbackResolver;
    }

    public object GetService(Type serviceType)
    {
        if ((this._resolver.IsRegistered(serviceType)) || (serviceType.IsClass))
        {
            try
            {
                return this._resolver.GetService(serviceType);
            }
            catch (ResolutionFailedException)
            {
            }
        }
        return this._fallbackResolver.GetService(serviceType);
    }

然后，在

Application\u Start（）

中，使用此代理的实例覆盖MVC解析器，如下所示：

var bootstrapper = new Bootstrapper();
var resolver = bootstrapper.Run();
DependencyResolver.SetResolver(new MvcDependencyResolver(resolver, DependencyResolver.Current));

---

你们有旅行社吗？您是否为MVC设置了依赖项解析器？