长字符串的剪裁(后台方式)

/// <summary>
/// 提供字符串操作
/// </summary>
    public static class StringHelper
    {
        /// <summary>
        /// 按照指定的长度剪裁字符串
        /// </summary>
        /// <param name="originalString">原始字符串</param>
        /// <param name="length">剪裁长度</param>
        /// <returns>剪裁后的字符串</returns>
        public static string CropString(string originalString, int length)
        {
            if (length < originalString.Length)
            {
                return originalString.Substring(0, length) + "...";
            }
            else return originalString;
        }
        /// <summary>
        /// 按照指定的长度可区分中英文剪裁字符串
        /// </summary>
        /// <param name="originalString">原始字符串</param>
        /// <param name="length">剪裁长度</param>
        /// <param name="isSeparate">是否区分中英文</param>
        /// <returns>剪裁后的字符串</returns>
        public static string CropString(string originalString, int length, bool isSeparate)
        {
            if (!isSeparate)
            {
                return CropString(originalString, length);
            }
            else
            {
                int len = length;
                for (int i = 0; i < (length > originalString.Length ? originalString.Length : length); i++)
                {
                    Regex rx = new Regex("^[\u4e00-\u9fa5]$"); 
                    if (!rx.IsMatch(originalString[i].ToString()))
                    {
                        len++;
                    }
                }
                return CropString(originalString, len);
            }
        }
}