升級到 Visual Studio 2012 RC 後出現 ASP.NET Web API 錯誤：找不到方法：‘Void System.Net.Http.Headers.HttpHeaders.AddWithoutValidation

升級到 Visual Studio 2012 後，我無法再訪問任何 ApiController，引發以下錯誤：

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決這個問題？

您在項目中引用了舊版本的 System.Net.Http。要解決此問題，請轉到項目中的“參考”下，刪除 System.Net.Http，然後添加 .NET 4.5 附帶的版本。那應該這樣做。

亨里克

在此處解決此問題和其他與 RC 相關的問題。

引用自：https://stackoverflow.com/questions/10862728