Common下StringHelper.cs

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#string #random #html #byte #脚本 #regex

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本文介绍了一种使用C#进行字符串处理的方法，包括截取、去除HTML标签、生成随机数等实用功能。通过具体的代码实现，展示了如何高效地操作字符串。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Web;

namespace Common
{
    public class StringHelper
    {
        public static string SubStr(string sString, int nLeng)
        {
            if (sString.Length <= nLeng)
            {
                return sString;
            }
            else
            {
                return sString.Substring(0, nLeng) + "...";
            }
        }

/// <summary>
        /// 清除脚本
        /// </summary>
        /// <param name="Htmlstring"></param>
        /// <returns></returns>
        public static string NoHTML(string Htmlstring)
        {
            //删除脚本
            Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "", RegexOptions.IgnoreCase);
            //删除HTML
            Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"([/r/n])[/s]+", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "/"", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", " ", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "/xa1", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "/xa2", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "/xa3", RegexOptions.IgnoreCase);
            Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "/xa9", RegexOptions.IgnoreCase); Htmlstring = Regex.Replace(Htmlstring, @"&#(/d+);", "", RegexOptions.IgnoreCase);
            Htmlstring.Replace("<", "");
            Htmlstring.Replace(">", "");
            Htmlstring.Replace("/r/n", "");
            Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();
            return Htmlstring;
        }
        /// <summary>
        /// 生成指定长度的随机数字串
        ///</summary>
        ///<param name="length">长度</param>
        ///<returns></returns>
       public static string RndStr(int length)
        {
            Random rnd = new Random();
            string returnstring = "";
            int i = 1;
            while (i <= length)
            {
                returnstring += rnd.Next(0, 9).ToString();
                i++;
            }
            return returnstring;
        }

/// <summary>
        /// 截取字符串，保留其HTML格式
        /// </summary>
        /// <param name="strText"></param>
        /// <param name="len"></param>
        /// <returns></returns>
        public static string CutWithSubstring(string strText, int len)
        {
            if (strText.Length > len)
            {
                return strText.Substring(0, len) + "…";
            }
            else
            {
                return strText;
            }
        }

public static string LoseHtml(string ContentStr)
        {
            string ClsTempLoseStr = "";
            System.Text.RegularExpressions.Regex regEx = new System.Text.RegularExpressions.Regex("<///*[^<>]*>");
            ClsTempLoseStr = regEx.Replace(ContentStr, "");
            return ClsTempLoseStr;
        }

/// <summary>
        /// 截取字符串去掉其HTML字符
        /// </summary>
        /// <param name="inputString"></param>
        /// <param name="len"></param>
        /// <returns></returns>
        public static string CutWithOutHtml(string inputString, int len)
        {
            int tempLen = 0;
            string tempString = "";
            inputString = LoseHtml(inputString);
            ASCIIEncoding ascii = new ASCIIEncoding();

            byte[] s = ascii.GetBytes(inputString);
            for (int i = 0; i < s.Length; i++)
            {
                if ((int)s[i] == 63)
                {
                    tempLen += 2;
                }
                else
                {
                    tempLen += 1;
                }

                try
                {
                    tempString += inputString.Substring(i, 1);
                }
                catch
                {
                    break;
                }

                if (tempLen > len)
                    break;
            }
            //如果截过则加上半个省略号
            byte[] mybyte = System.Text.Encoding.Default.GetBytes(inputString);
            if (mybyte.Length > len)
            {
                tempString = tempString.Substring(0, tempString.Length - 3 == 0 ? 1 : tempString.Length - 3) + "…";
            }
            return tempString;
        }

}
}