c#截取字符串，經過驗證的

 public class SubStrBeautiful
    {
        /// <summary>
        /// 截取字符串
        /// </summary>
        /// <param name="str">需要截取的字符串</param>
        /// <param name="strlen">字符串的長度</param>
        /// <param name="end">當這能截取一部分的時候 沒有截取到的時候用字符串代替 爲空就是不代替了</param>
        /// <returns></returns>
        public static string cutStr(string str, int strlen, string end)
        {
            str = str.Replace("\r", "").Replace("\n", "");
            System.Text.Encoding encode = System.Text.Encoding.GetEncoding("gb2312");
            byte[] data = encode.GetBytes(str);
            if (data.Length <= strlen) return str;
            string temp = encode.GetString(data, 0, strlen);
            temp = str.Substring(0, temp.Length) + end;
            return temp;
        }


        public static bool IsChinese(char c)
        {
            return (int)c > 0x4E00 && (int)c < 0x9FA5;
        }
    }