以下是我遇到的症状:
我在一个区域有一个全新的空控制器:
public class JamController : Controller
{
public JamController()
{
throw new Exception("Not implemented!");
}
如果我访问http://myprojectserver.example.com:12345/urlthatdoesnotexist,我会收到以下错误:
[CompositionException: The composition produced a single composition error. The root cause is provided below. Review the CompositionException.Errors property for more detailed information.
1) Not implemented!
Resulting in: An exception occurred while trying to create an instance of type 'MyWebProject.Areas.Users.Controllers.JamController'.
Resulting in: Cannot activate part 'MyWebProject.Areas.Users.Controllers.JamController'.
Element: MyWebProject.Areas.Users.Controllers.JamController --> MyWebProject.Areas.Users.Controllers.JamController
Resulting in: Cannot get export 'MyWebProject.Areas.Users.Controllers.JamController (ContractName="System.Web.Mvc.IController")' from part 'MyWebProject.Areas.Users.Controllers.JamController'.
Element: MyWebProject.Areas.Users.Controllers.JamController (ContractName="System.Web.Mvc.IController")
]
System.ComponentModel.Composition.Hosting.CompositionServices.GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition) +55
System.ComponentModel.Composition.Hosting.CatalogExportProvider.GetExportedValue(CatalogPart part, ExportDefinition export, Boolean isSharedPart) +78
System.ComponentModel.Composition.Hosting.CatalogExport.GetExportedValueCore() +47
System.ComponentModel.Composition.Primitives.Export.get_Value() +57
System.ComponentModel.Composition.ExportServices.GetCastedExportedValue(Export export) +40
System.ComponentModel.Composition.<>c__DisplayClassa`1.<CreateStronglyTypedLazyOfT>b__6() +39
System.Lazy`1.CreateValue() +416
System.Lazy`1.LazyInitValue() +382
System.Lazy`1.get_Value() +75
MefContrib.Web.Mvc.<>c__DisplayClass4.<GetControllerType>b__0(Lazy`1 e) +53
System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +204
System.Collections.Generic.List`1..ctor(IEnumerable`1 collection) +381
System.Linq.Enumerable.ToList(IEnumerable`1 source) +58
MefContrib.Web.Mvc.CompositionControllerFactory.GetControllerType(RequestContext requestContext, String controllerName) +412
System.Web.Mvc.DefaultControllerFactory.System.Web.Mvc.IControllerFactory.GetControllerSessionBehavior(RequestContext requestContext, String controllerName) +61
System.Web.Mvc.MvcRouteHandler.GetSessionStateBehavior(RequestContext requestContext) +122
System.Web.Mvc.MvcRouteHandler.GetHttpHandler(RequestContext requestContext) +33
System.Web.Mvc.MvcRouteHandler.System.Web.Routing.IRouteHandler.GetHttpHandler(RequestContext requestContext) +10
System.Web.Routing.UrlRoutingModule.PostResolveRequestCache(HttpContextBase context) +9709884
System.Web.Routing.UrlRoutingModule.OnApplicationPostResolveRequestCache(Object sender, EventArgs e) +82
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +136
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +699
我的问题是“为什么?” 为什么它试图实例化这个控制器?我在哪里可以确定是什么原因造成的。我很确定在“找不到页面”上实例化每个控制器不是预期的行为。
我不知道该去哪里找。有人可以指出我的方向吗?
更新:
原来是下面的 SetControllerFactory 方法导致了这个问题:
// Tell MVC3 to use MEF as its dependency resolver.
var dependencyResolver = new CompositionDependencyResolver(catalog);
DependencyResolver.SetResolver(dependencyResolver);
// Tell MVC3 to resolve dependencies in controllers
ControllerBuilder.Current.SetControllerFactory(
new CompositionControllerFactory(
new CompositionControllerActivator(dependencyResolver)));
注释掉“告诉 MVC3 解决控制器中的依赖关系”部分解决了我的问题,除了我要求的控制器之外,没有控制器被实例化。幸运的是,只有在您不使用标准 Asp.Net 控制器分辨率时才需要这样做(我们也是)。