What is the most efficient way to perform the reverse of Server.MapPath in an ASP.Net Application

Question

I am building an MVC application in which I am reading a list of files from the file system and I want to pass the relative URL to that file to the view, preferably prefixed with "~/" so that whatever view is selected cab render the URL appropriately.

To do this, I need to enumerate the files in the file system and convert their physical paths back to relative URLs. There are a few algorithms I've experimented with, but I am concerned about efficiency and minimal string operations. Also, I believe there's nothing in the .Net Framework that can perform this operation, but is there something in the latest MVC release that can?

Answer 1

At the moment I don't know any built-in method to do it, but it's not difficult, I do it like this:

• We need to get the Application root, and replace it in our new path with ~
• We need to convert the backslashes to slashes

---

public string ReverseMapPath(string path)
{
    string appPath = HttpContext.Current.Server.MapPath("~");
    string res = string.Format("~{0}", path.Replace(appPath, "").Replace("\\", "/"));
    return res;
}