Csharp: Searching Within a String

 /// <summary>
    /// 20130118
    /// 搜索字符串
    /// 塗聚文 締友計算機信息技術有限公司
    /// 捷為工作室
    /// </summary>
    public class StringSearchClass
    {
        /// <summary>
        /// 查找字符串
        /// StringIndexOf("1,2,3,4,5,6", "1,8");
        /// </summary>
        /// <param name="str1">字符串</param>
        /// <param name="judgestr">找查的字符串</param>
        /// <returns>返回是否存在</returns>
        public static bool StringIndexOf(string str1, string searchstr)
        {
            bool isExist = true;
            str1 = "," + str1 + ",";
            string[] strs = searchstr.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
            foreach (string strtemp in strs)
            {
                if (str1.IndexOf(',' + strtemp + ',') == -1)
                {
                    isExist = false;
                    break;
                }
            }
            return isExist;
        }
        /// <summary>
        /// 查找字符串 
        /// 塗聚文
        /// </summary>
        /// <param name="str1">字符串</param>
        /// <param name="judgestr">找查的字符串</param>
        /// <returns></returns>
        public static bool StringContains(string str1, string searchstr)
        {
            bool isExist = true;
            str1 = "," + str1 + ",";
            string[] strs = searchstr.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
            foreach (string strtemp in strs)
            {
                if (!str1.Contains(',' + strtemp + ','))
                {
                    isExist = false;
                    break;
                }
            }
            return isExist;
        }
        /// <summary>
        /// 查找字符串
        /// 塗聚文
        /// </summary>
        /// <param name="str1">字符串</param>
        /// <param name="judgestr">找查的字符串</param>
        /// <returns></returns>
        public static bool StringRegex(string str1, string searchstr)
        {
            bool isExist = true;
            str1 = "," + str1 + ",";
            string[] strs = searchstr.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
            foreach (string strtemp in strs)
            {
                if (!Regex.Match(str1, strtemp, RegexOptions.IgnoreCase).Success)
                {
                    isExist = false;
                }
            }
            return isExist;
        }
    }

//測試
            Stopwatch sw = new Stopwatch();
            
            sw.Start();
           // bool s = StringIndexOf("1,2,3,4,5,6", "1,6");//True,所耗時間：00:00:00.0003557
           // bool s = StringContains("1,2,3,4,5,6", "1,6");//True,所耗時間：00:00:00.0003625
            bool s = StringRegex("1,2,3,4,5,6", "1,6");//False,所耗時間：00:00:00.0286617 //True,所耗時間：00:00:00.0008295 //True,所耗時間：00:00:00.0008237
           sw.Stop();
           this.textBox1.Text=s.ToString()+",所耗時間："+sw.Elapsed.ToString();