I get the following exception after installing ASP.NET MVC 4 Beta on a machine with ASP.NET MVC 3.
System.InvalidCastException was unhandled by user code Message=[A]System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to [B]System.Web.WebPages.Razor.Configuration.HostSection. Type A originates from 'System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' in the context 'Default' at location 'C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.WebPages.Razor\v4.0_1.0.0.0__31bf3856ad364e35\System.Web.WebPages.Razor.dll'. Type B originates from 'System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' in the context 'Default' at location 'C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Web.WebPages.Razor\v4.0_2.0.0.0__31bf3856ad364e35\System.Web.WebPages.Razor.dll'. Source=System.Web.WebPages.Razor
StackTrace:
at System.Web.WebPages.Razor.WebRazorHostFactory.GetRazorSection(String virtualPath) at System.Web.WebPages.Razor.WebRazorHostFactory.CreateHostFromConfig(String virtualPath, String physicalPath) at System.Web.WebPages.Razor.RazorBuildProvider.GetHostFromConfig() at System.Web.WebPages.Razor.RazorBuildProvider.CreateHost() at System.Web.WebPages.Razor.RazorBuildProvider.EnsureGeneratedCode() at System.Web.WebPages.Razor.RazorBuildProvider.get_CodeCompilerType() at System.Web.Compilation.BuildProvider.GetCompilerTypeFromBuildProvider(BuildProvider buildProvider) at System.Web.Compilation.BuildProvidersCompiler.ProcessBuildProviders() at System.Web.Compilation.BuildProvidersCompiler.PerformBuild() at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate) at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate) at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound) at System.Web.Mvc.BuildManagerWrapper.System.Web.Mvc.IBuildManager.FileExists(String virtualPath) at System.Web.Mvc.BuildManagerViewEngine.FileExists(ControllerContext controllerContext, String virtualPath) at System.Web.Mvc.VirtualPathProviderViewEngine.GetPathFromGeneralName(ControllerContext controllerContext, List`1 locations, String name, String controllerName, String areaName, String cacheKey, String[]& searchedLocations) at System.Web.Mvc.VirtualPathProviderViewEngine.GetPath(ControllerContext controllerContext, String[] locations, String[] areaLocations, String locationsPropertyName, String name, String controllerName, String cacheKeyPrefix, Boolean useCache, String[]& searchedLocations) at System.Web.Mvc.VirtualPathProviderViewEngine.FindView(ControllerContext controllerContext, String viewName, String masterName, Boolean useCache) at System.Web.Mvc.ViewEngineCollection.<>c__DisplayClassc.b__b(IViewEngine e) at System.Web.Mvc.ViewEngineCollection.Find(Func`2 lookup, Boolean trackSearchedPaths) at System.Web.Mvc.ViewEngineCollection.FindView(ControllerContext controllerContext, String viewName, String masterName) at System.Web.Mvc.ViewResult.FindView(ControllerContext context) at System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.b__19() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1c.<>c__DisplayClass1e.b__1b() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) at System.Web.Mvc.Controller.ExecuteCore() at [project_namespace].Controllers.GlobalizationController.ExecuteCore() in [file_path] at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) at System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<>c__DisplayClassb.b__5() at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.b__0() at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass8`1.b__7(IAsyncResult _) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End() at System.Web.Mvc.MvcHandler.<>c__DisplayClasse.b__d() at System.Web.Mvc.SecurityUtil.b__0(Action f) at System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action) at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
This blocks me completely and while I would like to keep the beta, I might need to remove it completely in order to get rid of the exception.
Try adding the following in your web.config:
The issue might be due to multiple build providers being registered and the latest winning.
If you are experiencing this issue and you have tried the solutions above and this not work, pls check the web.config in your Views folder. There may be some configurations their that is conflicting the Web.config file in your App root folder
Some of your code is running on the current MVC bits, while others have been pushed out to the newer. Without understanding the code, I can't tell you what specific bit is causing the issue.
Having said that, I would never set up a beta on a production development machine. It is too easy to create a VM these days and run the beta on an image. In Windows 7+, you can boot the image off the metal and not take the perf hit, if you need that (with dev tool betas, you oft do).
You will notice:
System.Web.WebPages.Razor
changes fromVersion=1.0.0.0
toVersion=2.0.0.0
System.Web.Mvc
changes fromVersion=3.0.0.0
toVersion=4.0.0.0
Also as last step clear your bin folder from the project where the error is coming from.
One more, rather late, solution ... I ran into this same problem. Did all the fixes listed here (Thank You All!!!) but could not get past the error. Finally, in desperation, I found a web.config file in the Views directory. In this file, I found several references to the version of System.Web.Mvc and bumped all of them up to "4.0.0.0". More importantly, I found the following lines and updated the version numbers for "system.web.webPages.Razor" from "1.0.0.0" to "2.0.0.0" and suddenly, everything was working once again. Hopefully, this will help someone else.
Steve G.