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

The Question :

132 people think this question is useful

I’m trying to get the absolute path of certain files in a C# class. Server.MapPath works great of course for ASPX and their code-behind pages, but that doesn’t exist in another class file. I tried HostingEnvironment.MapPath(), but that complains that the relative virtual path isn’t allowed. Any thoughts?

System.Web is already imported.

The Question Comments :

The Answer 1

306 people think this answer is useful

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


You’ll have to import System.Web though.

The Answer 2

34 people think this answer is useful

you can also use:

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


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

is inaccessible

The Answer 3

8 people think this answer is useful

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.

The Answer 4

4 people think this answer is useful

IF the file you are trying to get is the assembly location for a type. But if the files are relative to the assembly location then you can use this with System.IO namespace to get the exact path of the file.

The Answer 5

4 people think this answer is useful

I use this too:


The Answer 6

3 people think this answer is useful
class test
public static void useServerPath(string path)
   if (File.Exists(path)
 \\...... do whatever you wabt

Now when you call the method from the codebehind

for example :

protected void BtAtualizacao_Click(object sender, EventArgs e)
             string path = Server.MapPath("Folder") + "\\anifile.txt";


in this way your code is to simple and with one method u can use multiple path for each call 🙂

The Answer 7

3 people think this answer is useful

This one helped for me

//System.Web.HttpContext.Current.Server.MapPath //        
FileStream fileStream = new FileStream(System.Web.HttpContext.Current.Server.MapPath("~/File.txt"),
FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);

The Answer 8

1 people think this answer is useful

Whether you’re running within the context of ASP.NET or not, you should be able to use HostingEnvironment.ApplicationPhysicalPath

The Answer 9

0 people think this answer is useful

The server.mappath(“”) will work on aspx page,if you want to get the absolute path from a class file you have to use this-


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