升级到 Visual Studio 2012 后,我无法再访问任何 ApiController,引发以下错误:
Server Error in '/' Application.
Method not found: 'Void System.Net.Http.Headers.HttpHeaders.AddWithoutValidation(System.String, System.Collections.Generic.IEnumerable`1<System.String>)'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.MissingMethodException: Method not found: 'Void System.Net.Http.Headers.HttpHeaders.AddWithoutValidation(System.String, System.Collections.Generic.IEnumerable`1<System.String>)'.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[MissingMethodException: Method not found: 'Void System.Net.Http.Headers.HttpHeaders.AddWithoutValidation(System.String, System.Collections.Generic.IEnumerable`1<System.String>)'.]
System.Web.Http.WebHost.HttpControllerHandler.AddHeaderToHttpRequestMessage(HttpRequestMessage httpRequestMessage, String headerName, String[] headerValues) +0
System.Web.Http.WebHost.HttpControllerHandler.ConvertRequest(HttpContextBase httpContextBase) +248
System.Web.Http.WebHost.HttpControllerHandler.BeginProcessRequest(HttpContextBase httpContextBase, AsyncCallback callback, Object state) +79
System.Web.Http.WebHost.HttpControllerHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +48
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +268
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17626
任何人都知道如何解决这个问题?