我的问题是我没有在我的项目中包含global.asax.cs。因为我是从。net 4.5复制文件到4.0，所以我没有注释掉4.0中不需要的行。因为它不包括visual studio编译它无论如何没有问题。但是当我加入它时，它突出显示了导致问题的行。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
//using System.Web.Http;
using System.Web.Mvc;
//using System.Web.Optimization;
using System.Web.Routing;

namespace YourNameSpace
{
    public class WebApiApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            //GlobalConfiguration.Configure(WebApiConfig.Register);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            //BundleConfig.RegisterBundles(BundleTable.Bundles);
        }
    }
}

I faced the problem in VS 2017 out of no where, took my whole day going through 100 of solutions any of these didnt work. I then took my whole solution and started it on different machine having VS 2017 installation.. IT FINALLY WORKED. Than reinstalled VS 2017 on the original one and it started running on that too. I strongly recommend you try your solution on a different machine before wasting much time to debug it, bcz it is a BUG in VS 2017 as it seemed for me, have reported same to VS TEAM. Hope this helps any one in grief. Cheers.

我也得到了同样的错误…检查您正确开发的应用程序的名称。分配的名称空间和程序集名称，并尝试物理地更改为应用程序创建的文件夹名称，所有这些都应该与文件global.asax中出现的上述名称空间中的名称相同

Yes, I read all the answers. However, if you are me and have been pulling out all of what's left of your hair, then try checking the \bin folder. Like most proj files might have several configurations grouped under the XML element PropertyGroup, then I changed the OutputPath value from 'bin\Debug' to remove the '\Debug' part and Rebuild. This placed the files in the \bin folder allowing the Express IIS to find and load the build. I am left wondering what is the correct way to manage these different builds so that a local debug deploy is able to find and load the target environment.

我不得不说，我尝试了这篇文章中的至少4条建议。没有一个成功。然而，我很高兴地告诉大家，我从备份中恢复过来了。只需要更新日志文件中最后的代码更改。花了不到10分钟。花了3倍的时间阅读这篇文章并尝试其他建议。对不起。

这是一个非常奇怪的错误。祝其他遇到这个小妖精的人好运。

我不得不去BUILD ->配置管理器，然后——咳咳——勾选我的项目旁边的复选框，以确保它实际上得到了构建。