abp/framework/src/Volo.Abp.Validation/Volo/Abp/Validation/ValidationHandler.cs

using System.Text.RegularExpressions;

namespace Volo.Abp.Validation
{
    public class ValidationHandler
    {
        private const string EmailRegEx = @"[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?";

        public static bool IsValidEmailAddress(string email)
        {
            if (string.IsNullOrEmpty(email))
            {
                return false;
            }

            /*RFC 2822 (simplified)*/
            return Regex.IsMatch(email, EmailRegEx, RegexOptions.Compiled | RegexOptions.IgnoreCase);
        }
    }
}