how-to get the basedir of an web application in C# asp.net

public static string getBaseDir ()
{
string baseDirLocal = System.Web.HttpContext.Current.Server.MapPath ( "~" );
Regex Remover = new Regex ( @"^.*(\\|\/)(.*)$" ,
RegexOptions.IgnoreCase | RegexOptions.Compiled );
string bareDir = Remover.Replace ( baseDirLocal , "$2" );

string strToRemoveAtEnd= System.Web.HttpContext.Current.Request.Url.AbsolutePath;
char [] charsToRemoveAtEnd = strToRemoveAtEnd.ToCharArray ();
string baseDir = System.Web.HttpContext.Current.Request.Url.AbsoluteUri;
baseDir = baseDir.TrimEnd ( charsToRemoveAtEnd );
baseDir = baseDir + "/" + bareDir + "/";
return baseDir;
} //eof method getBaseDir