<Reference Include="System.Web.WebPages"/><ReferenceInclude="System.Web.Helpers"/>
修改成
<Reference Include="System.Web.WebPages, Version=1.0.0.0,Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL "/> <Reference Include="System.Web.Helpers, Version=1.0.0.0,Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL" />