（一）利用正则表达式 进行字符的判断

【转】http://blog.csdn.net/dingxiaowei2013/article/details/8571757

using System;
using System.Text.RegularExpressions;
using System.NET;

namespace 正则表达式检测字符串
{
    class Program
    {
        static void Main(string[] args)
        {
            
            Console.WriteLine("请输入字符串：");
            string s = Console.ReadLine();
            if (GF_IsOk.IsExistHanZi(s))
            {
                Console.Write("包含汉字");
            }
            else
            {
                Console.Write("不包含汉字");
            }
            Console.ReadLine();
        }
    }
    //判断部分
    public class GF_IsOk
    {
        /// <summary>
        /// 判读是否是IP地址
        /// </summary>
        /// <param name="in_str"></param>
        /// <returns></returns>
        public static bool IsIPStr(string in_str)
        {
            IPAddress ip;
            return IPAddress.TryParse(in_str, out ip);
        }

        /// <summary>
        /// 判断是否是数字
        /// </summary>
        /// <param name="strNumber"></param>
        /// <returns></returns>
        public static bool IsNumber(string strNumber)
        {

            Regex objNotNumberPattern = new Regex("[^0-9.-]");
            Regex objTwoDotPattern = new Regex("[0-9]*[.][0-9]*[.][0-9]*");
            Regex objTwoMinusPattern = new Regex("[0-9]*[-][0-9]*[-][0-9]*");
            String strValidRealPattern = "^([-]|[.]|[-.]|[0-9])[0-9]*[.]*[0-9]+$";
            String strValidIntegerPattern = "^([-]|[0-9])[0-9]*$";
            Regex objNumberPattern = new Regex("(" + strValidRealPattern + ")|(" + strValidIntegerPattern + ")");
            return !objNotNumberPattern.IsMatch(strNumber) &&
                   !objTwoDotPattern.IsMatch(strNumber) &&
                   !objTwoMinusPattern.IsMatch(strNumber) &&
                   objNumberPattern.IsMatch(strNumber);
        }

        /// <summary>
        ///  判断是否是日期字符串
        /// </summary>
        /// <param name="in_str"></param>
        /// <returns></returns>
        public static bool IsDateStr_yyyymmdd(string in_str)
        {
            if (in_str == "") return true;
            if (in_str.Length != 8) return false;
            return IsDateStr(in_str);
        }

        /// <summary>
        /// 判断是否是日期字符串
        /// </summary>
        /// <param name="in_str"></param>
        /// <returns></returns>
        public static bool IsDateStr(string in_str)
        {
            if (in_str == "") return true;
            if (in_str.Length == 8)
                in_str = in_str.Substring(0, 4) + "-" + in_str.Substring(4, 2) + "-" + in_str.Substring(6, 2);
            DateTime dtDate;
            bool bValid = true;
            try
            {
                dtDate = DateTime.Parse(in_str);
            }
            catch (FormatException)
            {
                // 如果解析方法失败则表示不是日期性数据
                bValid = false;
            }
            return bValid;
        }

        /// <summary>
        /// 判断字符串中是否包含汉字,有返回true 否则为false
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static bool IsExistHanZi(string str)
        {
            Regex reg = new Regex(@"[\u4e00-\u9fa5]");//正则表达式
            if (reg.IsMatch(str))
            {
                return true;
            }
            else
            {
                return false;
            }
        }


        /// <summary>
        /// 字段串是否为Null或为""(空)
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static bool IsStrNullOrEmpty(string str)
        {
            if (str == null || str.Trim() == string.Empty)
                return true;

            return false;
        }

        /// <summary>
        /// 返回文件是否存在
        /// </summary>
        /// <param name="filename">文件名</param>
        /// <returns>是否存在</returns>
        public static bool IsFileExists(string filename)
        {
            return System.IO.File.Exists(filename);
        }


        /// <summary>
        /// 检测是否符合email格式
        /// </summary>
        /// <param name="strEmail">要判断的email字符串</param>
        /// <returns>判断结果</returns>
        public static bool IsValidEmail(string strEmail)
        {
            return Regex.IsMatch(strEmail, @"^[\w\.]+([-]\w+)*@[A-Za-z0-9-_]+[\.][A-Za-z0-9-_]");
        }

        public static bool IsValidDoEmail(string strEmail)
        {
            return Regex.IsMatch(strEmail, @"^@((

[0−9]1,3\.[0−9]1,3\.[0−9]1,3\.)|(([\w−]+\.)+))([a−zA−Z]2,4|[0−9]1,3)(
?)$");
        }
        /// <summary>
        /// 检测是否是正确的Url
        /// </summary>
        /// <param name="strUrl">要验证的Url</param>
        /// <returns>判断结果</returns>
        public static bool IsURL(string strUrl)
        {
            return Regex.IsMatch(strUrl, @"^(http|https)\://([a-zA-Z0-9\.\-]+(\:[a-zA-Z0-9\.&%\$\-]+)*@)*((25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])|localhost|([a-zA-Z0-9\-]+\.)*[a-zA-Z0-9\-]+\.(com|edu|gov|int|mil|net|org|biz|arpa|info|name|pro|aero|coop|museum|[a-zA-Z]{1,10}))(\:[0-9]+)*(/($|[a-zA-Z0-9\.\,\?\'\\\+&%\$#\=~_\-]+))*$");
        }

 

        /// <summary>
        /// 判断是否为base64字符串
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static bool IsBase64String(string str)
        {
            //A-Z, a-z, 0-9, +, /, =
            return Regex.IsMatch(str, @"[A-Za-z0-9\+\/\=]");
        }

        /// <summary>
        /// 检测是否有Sql危险字符
        /// </summary>
        /// <param name="str">要判断字符串</param>
        /// <returns>判断结果</returns>
        public static bool IsSafeSqlString(string str)
        {
            return !Regex.IsMatch(str, @"[-|;|,|\/|||

|
|\}|\{|%|@|\*|!|\']");
        }
    }
}