30/09/2018
        public static Boolean DeleteFile(string FileName)...
       /// <summary>
        /// Ham xoa file
        /// </summary>
        /// <param name="FileName"></param>
        /// <returns>Tra ve true neu thanh cong, false neu khong thanh cong</returns>
        public static Boolean DeleteFile(string FileName)
        {
            try
            {
                File.Delete(FileName);
                return true;
            }
            catch
            {
                return false;
            }
        }