How can I make a textbox only accept a valid email?

Question

I would like my textbox to check if the email that is entered into the textbox is valid.

So far I have got:

if (!this.txtEmail.Text.Contains('@') || !this.txtEmail.Text.Contains('.')) 
{ 
    MessageBox.Show("Please Enter A Valid Email", "Invalid Email", MessageBoxButtons.OK, MessageBoxIcon.Error); 
}

But this only tests if it has a '@' and a '.' in it.

Is there a way to make it check to see if it has .com etc. and only one '@'?

Validating email addresses is difficult. The easiest way is to do, what you already did: look for `@` and `.`. If those are present, send an email to that address and let the user confirm its authenticity. — germi, Apr 23 '15 at 10:35
Most of the different UI (and web) frameworks in the C# space have validators, and usually also one specifically for validating email addresses. — Mark Rotteveel, Apr 23 '15 at 14:09

score 7 · Accepted Answer · edited Sep 10 '21 at 09:15

7

.NET can do it for you:

  bool IsValidEmail(string eMail)
  {
     bool Result = false;

     try
     {
        var eMailValidator = new System.Net.Mail.MailAddress(eMail);

        Result = (eMail.LastIndexOf(".") > eMail.LastIndexOf("@"));
     }
     catch
     {
        Result = false;
     };

     return Result;
  }

edited Sep 10 '21 at 09:15

Michael

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answered Apr 23 '15 at 10:25

Jack

350
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15

If i use "test@test" this passes as a valid email address using this approach. – DDuffy Oct 13 '16 at 12:15
Although it is useful, it doesn't check for a correct email address format, like @DDuffy said, passing "test@test" results as a "valid" email. – Jesús Hagiwara Jul 27 '19 at 15:20

score 0 · Answer 2 · edited Aug 29 '18 at 16:12

0

Check the MailAddress class

    var email = new MailAddress("abc123@example.com");

edited Aug 29 '18 at 16:12

its4zahoor

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23

answered Apr 23 '15 at 10:25

Matheno

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score 0 · Answer 3 · answered Apr 23 '15 at 12:14

If you're developing a web app, modern browsers support HTML5, so you can use <input id="txtEmail" type="email" runat="server" /> instead of a TextBox and it will validate the input is an email in the browser (but you should also validate it in your code). Use txtEmail.Value to get the text string.

How can I make a textbox only accept a valid email?

3 Answers3