BWPM/BlazorApp/Helper/Utils.cs

using System;
using System.Globalization;
using System.Text.RegularExpressions;


namespace BlazorApp.Helper
{
    public class Utils
    {
        public bool IsValidEmail(string email)
        {

                //return false;

            try
            {
                // Normalize the domain
                email = Regex.Replace(email, @"(@)(.+)$", DomainMapper,
                                      RegexOptions.None, TimeSpan.FromMilliseconds(200));

                // Examines the domain part of the email and normalizes it.
                string DomainMapper(Match match)
                {
                    // Use IdnMapping class to convert Unicode domain names.
                    var idn = new IdnMapping();

                    // Pull out and process domain name (throws ArgumentException on invalid)
                    string domainName = idn.GetAscii(match.Groups[2].Value);

                    return match.Groups[1].Value + domainName;
                }
            }
            catch (RegexMatchTimeoutException e)
            {
                return false;
            }
            catch (ArgumentException e)
            {
                return false;
            }

            try
            {
                return Regex.IsMatch(email,
                    @"^[^@\s]+@[^@\s]+\.[^@\s]+$",
                    RegexOptions.IgnoreCase, TimeSpan.FromMilliseconds(250));
            }
            catch (RegexMatchTimeoutException)
            {
                return false;
            }
        }
    }
}