当编译我的项目时，我得到的错误：

The type name ‘TagBuilder’ could not be found. This type has been forwarded to assembly ‘System.Web.WebPages,Version=1.0.0.0,Culture=neutral,PublicKeyToken=31bf3856ad364e35’. Consider adding a reference to that assembly.

但是该程序集不存在于GAC中(也不在添加引用对话框的.NET选项卡中)。搜索我的HDD不会打开具有该名称的DLL。