现在我们按照上面的方式运行我们的程序，在分别输入错误的用户名和密码的情况下会自动显现相应的错误页面。
四、自定义ActionInvoker：ExceptionActionInvoker
对于上述的两种不同的异常处理方式最终是通过自定义的ActionInvoker来实现的，我们将其命名为ExceptionActionInvoker。如下面的代码片断所式，ExceptionActionInvoker直接继承自ControllerActionInvoker。属性ExceptionPolicy是一个基于指定的异常策略名称创建的ExceptionPolicyImpl 对象，用于针对EntLib进行的异常处理。而属性GetErrorView是一个用于获得作为错误页面的ViewResult对象的委托。整个异常处理的核心定义在InvokeAction方法中，该方法中指定的handleErrorActionName参数代表的是“异常处理操作名称”，整个方法就是按照上述的异常处理策略实现的。
- usingSystem;
- usingSystem.Collections.Generic;
- usingSystem.Linq;
- usingSystem.Web;
- usingSystem.Web.Mvc;
- usingArtech.Mvc.ExceptionHandling.Configuration;
- usingMicrosoft.Practices.EnterpriseLibrary.Common.Configuration;
- usingMicrosoft.Practices.EnterpriseLibrary.ExceptionHandling;
- namespaceArtech.Mvc.ExceptionHandling
- {
- publicclassExceptionActionInvoker: ControllerActionInvoker
- {
- protectedExceptionHandlingSettings ExceptionHandlingSettings{get; privateset;}
- protectedvirtualFunc<string, HandleErrorInfo, ViewResult> GetErrorView { get; privateset; }
- publicExceptionPolicyImpl ExceptionPolicy { get; privateset; }
- publicExceptionActionInvoker(stringexceptionPolicy,Func<string, HandleErrorInfo, ViewResult> getErrorView)
- {
- this.ExceptionPolicy = EnterpriseLibraryContainer.Current.GetInstance<ExceptionPolicyImpl>(exceptionPolicy);
- this.GetErrorView = getErrorView;
- this.ExceptionHandlingSettings = ExceptionHandlingSettings.GetSection();
- }
- publicoverrideboolInvokeAction(ControllerContext controllerContext, stringhandleErrorActionName)
- {
- ExceptionContext exceptionContext = controllerContext asExceptionContext;
- if(null== exceptionContext)
- {
- thrownewArgumentException("The controllerContext must be ExceptionContext!", "controllerContext");
- }
- try
- {
- exceptionContext.ExceptionHandled = true;
- if(this.ExceptionPolicy.HandleException(exceptionContext.Exception))
- {
- HandleRethrownException(exceptionContext);
- }
- else
- {
- if(ExceptionHandlingContext.Current.Errors.Count == 0)
- {
- ExceptionHandlingContext.Current.Errors.Add(exceptionContext.Exception.Message);
- }
- ControllerDescriptor controllerDescriptor = this.GetControllerDescriptor(exceptionContext);
- ActionDescriptor handleErrorAction = FindAction(exceptionContext, controllerDescriptor, handleErrorActionName);
- if(null!= handleErrorAction)
- {
- IDictionary<string, object>parameters = GetParameterValues(controllerContext, handleErrorAction);
- exceptionContext.Result = this.InvokeActionMethod(exceptionContext, handleErrorAction, parameters);
- }
- else
- {
- HandleRethrownException(exceptionContext);
- }
- }
- returntrue;
- }
- catch(Exception ex)
- {
- exceptionContext.Exception = ex;60:HandleRethrownException(exceptionContext);
- returntrue;
- }
- }
- protectedvirtualvoidHandleRethrownException(ExceptionContext exceptionContext)
- {
- stringerrorViewName = this.GetErrorViewName(exceptionContext.Exception.GetType());
- stringcontrollerName = (string)exceptionContext.RouteData.GetRequiredString("controller");
- stringaction = (string)exceptionContext.RouteData.GetRequiredString("action");
- HandleErrorInfo handleErrorInfo = newHandleErrorInfo(exceptionContext.Exception, controllerName, action);70:exceptionContext.Result = this.GetErrorView(errorViewName, handleErrorInfo);
- }
- protectedstringGetErrorViewName(Type exceptionType)
- {
- ExceptionErrorViewElement element = ExceptionHandlingSettings.ExceptionErrorViews75:.Cast<ExceptionErrorViewElement>().FirstOrDefault(el=>el.ExceptionType == exceptionType);
- if(null!= element)
- {
- returnelement.ErrorView;
- }
- if(null== element &&null!= exceptionType.BaseType!= null)
- {
- returnGetErrorViewName(exceptionType.BaseType);
- }
- else
- {
- return"Error";
- }
- }
- }
- }
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