I’ve just downloaded and opened the mailer tutorial
http://docs.hangfire.io/en/latest/tutorials/send-email.html#installing-postal in Visual Studios 2013.
For some reason, all the “@Html”, “@ViewBag”, Model… variables in Views/Home/Create, Index.cshtml and Shared/_Layout.cshtml have an error: “The Name <@Html | @ ViewBag …> Does not exist in the current context”.
@Jiarui_Hou, is your question still actual? If yes, when your error occurs, during the build process or it is a ReSharper tooltips?
Errors are not during the build, but rather as a tooltip.
So just ignore them, ReSharper is no so smart with other than ASP.NET Razor files.