C# 字符串操作類

using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;
using System.Text.RegularExpressions;
using System.Security.Cryptography;
/××/
////////////////////////////////////////////////////
///功能：字符文本操作類
///
///
////////////////////////////////////////////////////
namespace XHW
{
    /// <summary>
    /// 字符文本操作類
    /// </summary>
    public class StringHelper
    {
        public static bool IsContains(string[] strs, string value)
        {
            if (strs == null)
            {
                return false;
            }

            foreach (string str in strs)
            {
                if (str == value)
                {
                    return true;
                }
            }

            return false;
        }



        #region 字符串過濾

        #region 對字符串進(jìn)行HTML編碼，針對(input,Textarea)輸入時過濾腳本及HTML編碼
        /××/
        /// <summary>
        /// 對字符串進(jìn)行HTML編碼，針對(input,Textarea)輸入時過濾腳本及HTML編碼
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        #endregion
        public static string EncodeToHtml(string source)
        {
            source = source.Trim();
            source = source.Replace("＇", "＇＇");
            source = source.Replace("\\", "＼");
            source = System.Web.HttpContext.Current.Server.HtmlEncode(source);
            source = source.Replace("\r\n", "<br>");
            source = source.Replace("\n", "<br>");
            return source;
        }


        #region [否決的]對字符串進(jìn)行HTML編碼，針對(input,Textarea)輸入時過濾腳本及HTML編碼
        /××/
        /// <summary>
        /// [否決的]對字符串進(jìn)行HTML編碼，針對(input,Textarea)輸入時過濾腳本及HTML編碼 (不符合命名規(guī)范，請使用 EncodeToHtml 方法 )
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        #endregion
        public static string HtmlFilterForInput(string source)
        {
            return EncodeToHtml(source);
        }


        #region 還原HTML編碼為字符串,還原HTML編碼為字符串，用于返回到input或 Textarea 輸入框
        /××/
        /// <summary>
        /// 還原HTML編碼為字符串，用于返回到input或 Textarea 輸入框
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        #endregion
        public static string DecodeFormHtml(string source)
        {
            source = source.Trim();
            source = source.Replace("<br>", "\r\n");
            source = source.Replace("<br>", "\n");
            source = System.Web.HttpContext.Current.Server.HtmlDecode(source);
            return source;
        }


        #region [否決的]還原HTML編碼為字符串,還原HTML編碼為字符串，用于返回到input或 Textarea 輸入框
        /××/
        /// <summary>
        /// [否決的]還原HTML編碼為字符串，用于返回到input或 Textarea 輸入框 (不符合命名規(guī)范，請使用 DecodeFormHtml 方法 )
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        #endregion
        public static string DeHtmlFilterForInput(string source)
        {
            source = source.Trim();
            source = source.Replace("<br>", "\r\n");
            source = source.Replace("<br>", "\n");
            source = System.