c# equivalent code for the script

Question

Hello All, 

I need below code equivalent in c#. Please help me

import java.util.regex.*

    // regex'
    String SPCHARS   = "\\p{Cntrl}\\(\\)<>@,;:'\\\\\\\"\\.\\[\\]"
    String VARS     = "(\\\\.)|[^\\s${SPECIAL_CHARS}]";
    String QUOTSER     = "(\"(\\\\\"|[^\"])*\")"
    String WORD            = "((${VALID_CHARS}|')+|${QUOTED_USER})"
    String EMREGEX                = "^\\s*?(.+)@(.+?)\\s*\$"
    String USREGEX       = "\\s*${WORD}(\\.${WORD})*"
    

Thanks in Advance

Chandu

Answer 1

You can use the MSDN function IsValidEmail from How to: Verify that Strings Are in Valid Email Format

Answer 2

Hi  ,

Thank you for posting here.

According to your description, you want to convert java code to c#.

Please refer to the following code.

static bool checkemail(string email)
        {
            String EMAIL_REGEX = @"[a-zA-Z0-9_-]+(\.[a-zA-Z0-9_-]+)+";
            String USER_REGEX = @"[A-Za-z0-9\u4e00-\u9fa5]+";
            int? MAX_USERNAME_LEN = 64;
            try
            {
                bool ismail = Regex.IsMatch(email, EMAIL_REGEX);
                if (email.IndexOf('@')==-1)
                {
                    return false;
                }
                else
                {
                    string user = email.Substring(0, email.LastIndexOf('@'));
                    bool isuservalid = Regex.IsMatch(email, USER_REGEX);
                    bool lengthcheck;
                    if(user.Length>MAX_USERNAME_LEN)
                    {
                        lengthcheck = false;
                    }
                    else
                    {
                        lengthcheck = true;
                    }
                    return ismail & isuservalid & lengthcheck;
                }

            }
            catch(Exception e)
            {
                Console.WriteLine(e.ToString());
                return false;
            }
        }

Hope my suggestion could be helpful.

Best regards,

Jack

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Answer 3

The following code library provides method to validate email addresses and goes into details how some approach are good vs bad, read the various "Strike" paragraphs as there are patterns that you may not have considered.

In the unit test for the library the following are used to test against.

namespace EmailAddressLibrary.Tests.CodeFool
{
    using System.Collections.Generic;

    /// <summary>
    /// Examples borrowed from the CodeFool blog.
    /// http://codefool.tumblr.com/post/15288874550/list-of-valid-and-invalid-email-addresses
    /// </summary>
    internal static class Examples
    {
        internal static IEnumerable<string> Valid =
            new[]
            {
                @"[e-mail]",
                @"[e-mail]",
                @"email@[123.123.123.123]",
                @"[e-mail]",
                @"[e-mail]",
                @"[e-mail]",
                @"[e-mail]",
                @"[e-mail]",
                @"[e-mail]",
                @"[e-mail]",
                @"[e-mail]",
                @"[e-mail]",
                @"""email""@example.com",
                @"あいうえお@example.com",
            };

        internal static IEnumerable<string> Invalid =
            new[]
            {
                @"#@%^%#$@#$@#.com",
                @"[e-mail]",
                @"@example.com",
                @"[e-mail]",
                @"Joe Smith <[e-mail]>",
                @"[e-mail]",
                @"[e-mail]",
                @"email.example.com",
                @"[e-mail]",
                @"email@111.222.333.44444",
                @"email@example",
                @"email@example..com",
                @"[e-mail] (Joe Smith)",
                @"email@[e-mail]",
                @"just""not""[e-mail]",
                @"plainaddress",
                @"this\ is""really""not\[e-mail]",
                @"""(),:;<>[]@example.com",
                @"email@123.123.123.123",
            };
    }
}

Basic usage

using EmailAddressLibrary;

EmailAddressValidator.Msdn("[e-mail]");            // True
EmailAddressValidator.ReferenceSource("[e-mail]"); // True
EmailAddressValidator.Haacked("[e-mail]");         // True
EmailAddressValidator.JStedfast("[e-mail]");       // True

---

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VB Forums - moderator

Answer 4

Evaluate this approach too:

static bool checkEmails( string email )
{
   try
   {
      new MailAddress( email );
      return true;
   }
   catch( FormatException )
   {
      return false;
   }
}