Get current directory in asp.net mvc

string TestX()
{
    string path = AppDomain.CurrentDomain.BaseDirectory; // You get main rott
    string dirc = ""; // just var for use
    string[] pathes = Directory.GetDirectories(path); // get collection

    foreach (string str in pathes)
    {
        if (str.Contains("NameYRDirectory")) // paste yr directory
        {
            dirc = str;
        }
    }

    return dirc; // after use Method and modify as you like
}

If controller is present at directory root

String path = ControllerContext.HttpContext.Server.MapPath(@"~/_xslt/example.xslt");

Else

String path = ControllerContext.HttpContext.Server.MapPath(@"../_xslt/example.xslt");

You can use the HttpServerUtility.MapPath method to map any relative paths for you, in your controller this is easily accessible via the ControllerContext:

string path = ControllerContext.HttpContext.Server.MapPath("~/_xslt/example.xslt");
...