Code-Validator：验证电子邮箱

using System;
using System.Text.RegularExpressions;

namespace Sp.Common
{
    public class ValidatorHelper
    {
        /// <summary>  
        /// 验证电子邮箱  
        /// [@字符前可以包含字母、数字、下划线和点号；@字符后可以包含字母、数字、下划线和点号；@字符后至少包含一个点号且点号不能是最后一个字符；最后一个点号后只能是字母或数字]  
        /// </summary>  
        /// <param name="input">待验证的字符串</param>  
        /// <returns>是否匹配</returns>  
        public static bool IsEmail(string input)
        {
            ////邮箱名以数字或字母开头；邮箱名可由字母、数字、点号、减号、下划线组成；邮箱名（@前的字符）长度为3～18个字符；邮箱名不能以点号、减号或下划线结尾；不能出现连续两个或两个以上的点号、减号。  
            //string pattern = @"^[a-zA-Z0-9]((?<!(\.\.|--))[a-zA-Z0-9\._-]){1,16}[a-zA-Z0-9]@([0-9a-zA-Z][0-9a-zA-Z-]{0,62}\.)+([0-9a-zA-Z][0-9a-zA-Z-]{0,62})\.?|((25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(25[0-5]|2[0-4]\d|[01]?\d\d?)$";  
            string pattern = @"^([\w-\.]+)@([\w-\.]+)(\.[a-zA-Z0-9]+)$";
            return IsMatch(input, pattern);
        }

        #region 匹配方法  
        /// <summary>  
        /// 验证字符串是否匹配正则表达式描述的规则  
        /// </summary>  
        /// <param name="inputStr">待验证的字符串</param>  
        /// <param name="patternStr">正则表达式字符串</param>  
        /// <returns>是否匹配</returns>  
        public static bool IsMatch(string inputStr, string patternStr)
        {
            return IsMatch(inputStr, patternStr, false, false);
        }

        /// <summary>  
        /// 验证字符串是否匹配正则表达式描述的规则  
        /// </summary>  
        /// <param name="inputStr">待验证的字符串</param>  
        /// <param name="patternStr">正则表达式字符串</param>  
        /// <param name="ifIgnoreCase">匹配时是否不区分大小写</param>  
        /// <returns>是否匹配</returns>  
        public static bool IsMatch(string inputStr, string patternStr, bool ifIgnoreCase)
        {
            return IsMatch(inputStr, patternStr, ifIgnoreCase, false);
        }

        /// <summary>  
        /// 验证字符串是否匹配正则表达式描述的规则  
        /// </summary>  
        /// <param name="inputStr">待验证的字符串</param>  
        /// <param name="patternStr">正则表达式字符串</param>  
        /// <param name="ifValidateWhiteSpace">是否验证空白字符串</param>  
        /// <returns>是否匹配</returns>  
        public static bool IsMatch1(string inputStr, string patternStr, bool ifValidateWhiteSpace)
        {
            return IsMatch(inputStr, patternStr, false, ifValidateWhiteSpace);
        }

        /// <summary>  
        /// 验证字符串是否匹配正则表达式描述的规则  
        /// </summary>  
        /// <param name="inputStr">待验证的字符串</param>  
        /// <param name="patternStr">正则表达式字符串</param>  
        /// <param name="ifIgnoreCase">匹配时是否不区分大小写</param>  
        /// <param name="ifValidateWhiteSpace">是否验证空白字符串</param>  
        /// <returns>是否匹配</returns>  
        public static bool IsMatch(string inputStr, string patternStr, bool ifIgnoreCase, bool ifValidateWhiteSpace)
        {
            if (!ifValidateWhiteSpace && string.IsNullOrEmpty(inputStr))
                return false;//如果不要求验证空白字符串而此时传入的待验证字符串为空白字符串，则不匹配  
            Regex regex = null;
            if (ifIgnoreCase)
                regex = new Regex(patternStr, RegexOptions.IgnoreCase);//指定不区分大小写的匹配  
            else
                regex = new Regex(patternStr);
            return regex.IsMatch(inputStr);
        }
        #endregion
    }
}