C#中英文字符串固定长度换行

        /// <summary>
        /// 字符串过程，换行
        /// </summary>
        /// <param name="contxt"></param>
        /// <returns></returns>
        private string DealwithContxt(string contxt, int length)
        {
            StringBuilder result = new StringBuilder();

            int len = 0;
            int star = 0;
            int templen = 0;
            for (int i = 0; i < contxt.Length; i++)
            {
                byte[] byte_len = Encoding.Default.GetBytes(contxt.Substring(i, 1));
                if (byte_len.Length > 1)
                    len += 2;
                else
                    len += 1;

                if (len >= length)
                {
                    templen = i - star;
                    result.Append(contxt.Substring(star, templen) + "\r\n");
                    star = i;
                    len = 0;
                }
                else if (i == contxt.Length - 1)
                {
                    result.Append(contxt.Substring(star) + "\r\n");
                    star = i;
                    len = 0;
                }

            }

            return result.ToString();
        }