public string GetHighVersion(string oldVersion)
            {
                byte[] array = new byte[1];
                array = System.Text.Encoding.ASCII.GetBytes(oldVersion); //string转换的字母
                int asciicode = (short)(array[0]);
                array[0] = (byte)(++asciicode); //ASCII码强制转换二进制
                return Convert.ToString(System.Text.Encoding.ASCII.GetString(array));
            }