Using Server.MapPath in external C# Classes in ASP.NET

The ServerUtility class is available as an instance in your HttpContext. If you're in an environment where you know it'll be executed inside the ASP.Net pipeline, you can use

HttpContext.Current.Server.MapPath()

You'll have to import System.Web though.

you can also use:

var path = System.Web.Hosting.HostingEnvironment.MapPath("~/App_Data/myfile.txt")

if

var path = Server.MapPath("~/App_Data");
var fullpath = Path.Combine(path , "myfile.txt");

is inaccessible

Can't you just add a reference to System.Web and then you can use Server.MapPath ?

Edit: Nowadays I'd recommend using the HostingEnvironment.MapPath Method:

It's a static method in System.Web assembly that Maps a virtual path to a physical path on the server. It doesn't require a reference to HttpContext.