ASP.NET网站无法在App_Code文件夹中看到.cs文件

So I have an ASP.NET web site (not web application) I'm making in VS2010 with C#. It runs fine on my machine, but when I upload it to the site it's hosted on, it won't compile, giving: "CS0246: The type or namespace name 'DataAccess' could not be found (are you missing a using directive or an assembly reference?)"So I have an ASP.NET web site (not web applicat