未能加載類型「System.Web.Http.WebHost.Routing.HttpRouteExceptionHandler」在單

Question

我試圖在單聲道使用最新的Asp.Net的Web API，但錯誤這樣表示：

System.TypeLoadException 
Could not load type 'System.Web.Http.WebHost.Routing.HttpRouteExceptionHandler' from assembly 'System.Web.Http.WebHost, Version=5.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. 

Description: HTTP 500.Error processing request. 
Details: Non-web exception. Exception origin (name of application or object): System.Web. 
Exception stack trace: 
    at System.Web.Routing.UrlRoutingModule.PostResolveRequestCache (System.Web.HttpContextBase context) [0x00054] in /Volumes/build-root-ramdisk/mono-3.4.0/mcs/class/System.Web.Routing/System.Web.Routing/UrlRoutingModule.cs:128 
    at System.Web.Routing.UrlRoutingModule.PostResolveRequestCache (System.Object o, System.EventArgs e) [0x00007] in /Volumes/build-root-ramdisk/mono-3.4.0/mcs/class/System.Web.Routing/System.Web.Routing/UrlRoutingModule.cs:88 
    at System.Web.HttpApplication+<RunHooks>c__Iterator0.MoveNext() [0x001ba] in /Volumes/build-root-ramdisk/mono-3.4.0/mcs/class/System.Web/System.Web/HttpApplication.cs:1050 
    at System.Web.HttpApplication+<Pipeline>c__Iterator1.MoveNext() [0x0073b] in /Volumes/build-root-ramdisk/mono-3.4.0/mcs/class/System.Web/System.Web/HttpApplication.cs:1260 
    at System.Web.HttpApplication.Tick() [0x00000] in /Volumes/build-root-ramdisk/mono-3.4.0/mcs/class/System.Web/System.Web/HttpApplication.cs:932 

Version Information: 3.4.0 ((no/c3fc3ba Thu May 1 22:52:17 EDT 2014); ASP.NET Version: 4.0.30319.17020 

而且我應該通過Nuget包含哪些dll？目前我引用了這些程序集：

- System (from GAC) 
- System.Web (from GAC) 
- System.Web.Http (from Nuget) 
- System.Net.Http.Formatting (from Nuget) 
- System.Web.Http.WebHost (from Nuget) 
- Newtonsoft.Json (from Nuget) 

Answer 1

Xamarin bugzilla中也有類似的錯誤。顯然，單aspnetwebstack首先需要更新才能使用最新的Web API庫：

https://bugzilla.xamarin.com/show_bug.cgi?id=19314

Answer 2

這可能可以通過周圍根本就沒有使用config.MapHttpAttributeRoutes();，而是手動指定的Web API途徑得到（例如config.Routes.MapHttpRoute .. ）。

Answer 3

我想我將我的回答爲時已晚，但我也有類似的問題，並進行調試，我添加以下行源代碼：

var httpHost = new System.Web.Http.WebHost.HttpControllerHandler(null); 

你瞧，編譯失敗（換行符是我的）：

Global.asax.cs(116,56): error CS1684: Reference to type 
`System.Web.HttpTaskAsyncHandler' claims it is defined assembly 
`System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a', 
    but it could not be found 

所以，基本上 - 是的。 Busted System.Web.dll