项目从Visual Studio 2013 升级到 2015 后出现错误解决方案


升级到VS2015后，Clear, 从新编译后，出现错误


Description: An exception occurred while processing your request. Additionally, another exception occurred while executing the custom error page for the first exception. The request has been terminated.


解决方案：


1. 修改 Web.config
<customErrors mode="Off" >

 编译运行，出现错误
Error: Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()' to access security critical method 'System.Web.WebPages.Razor.WebPageRazorHost.AddGlobalImport(System.String)' failed.


2. 安装程序包

   View -> Others windows -> Package Manager Console   或者   Tools > NuGet Package Manager > Package Manager Console

   PM> Install-Package Microsoft.AspNet.WebHelpers

  再编译，出现新错误
  Error：Could not load file or assembly 'WebMatrix.Data, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located   assembly's manifest definition does not match the assembly reference


3. 再安装程序包
    Tools > NuGet Package Manager > Package Manager Console

     PM> Install-Package Microsoft.AspNet.WebPages.Data

   再编译，运行正常，

4. 修改Web.config <customErrors mode="On" >

总结： 

       当项目升级到VS 2015.  若出现WebMatrix的错误，需要安装以下两个程序包：

Microsoft.AspNet.WebHelpers

Microsoft.AspNet.WebPages.Data