public static double DirectorySize(DirectoryInfo dirInfo)
{
   double total = 0;
   try
   {
      foreach(FileInfo file in dirInfo.GetFiles())
      {
         total += file.Length; 
      } 
      foreach(DirectoryInfo dir in dirInfo.GetDirectories())
      {
         total += DirectorySize(dir); 
      }
   }
   catch
   {
      return 0;
   }
   return total;
}