C#中如何利用正则表达式判断字符

废话不多说了，下面代码给大家介绍下利用正则表达式判断字符的方法，具体代码如下所示：

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, @"[-|;|,|\/|||
|
|\}|\{|%|@|\*|!|\']");
  }
 }
}

以上所述是小编给大家介绍的C#中如何利用正则表达式判断字符，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对呐喊教程网站的支持！