C#正则表达式校验某个字符串是否是合格的email

可以借助正则表达式校验某个字符串是否是合规的电子邮箱。对于邮箱的正则表达式有严格的模式，如：^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$
对应的C#实现如下：

using System;
using System.Text.RegularExpressions;

namespace EmailRegexValidateExample
{
    /// <summary>
    /// 如何确认字符串是有效的电子邮件格式
    /// https://learn.microsoft.com/zh-cn/dotnet/standard/base-types/how-to-verify-that-strings-are-in-valid-email-format
    /// </summary>
    internal class Program
    {
        public static string EMAIL_PATTERN = "^[a-zA-Z0-9_+&*-]+(?:\\.[a-zA-Z0-9_+&*-]+)*@(?:[a-zA-Z0-9-]+\\.)+[a-zA-Z]{2,7}$";
        /// <summary>
        /// 验证字符串email是否为有效的邮箱地址
        /// </summary>
        /// <param name="email"></param>
        /// <returns></returns>
        public static bool IsEmail(string email)
        {
            Regex regEmail = new Regex(EMAIL_PATTERN);
            Match match = regEmail.Match(email);
            return match.Success;
        }
        static void Main(string[] args)
        {
            string email1 = "alice@example.com";
            if (IsEmail(email1))
            {
                Console.WriteLine("email1 " + email1 + " is valid email address");
            } else {
                Console.WriteLine("email1 " + email1 + " is invalid email address");
            }

            string email2 = "alice..bob@example.com";
            if (IsEmail(email1))
            {
                Console.WriteLine("email2 " + email2 + " is valid email address");
            } else {
                Console.WriteLine("email2 " + email1 + " is invalid email address");
            }
        }
    }
}

执行结果如下图所示：