Re: validate an email address - C# Discussion Boards

7-Sep-09 9:24

how can I validate if the email address provided by the user does exists or not before proceeding to send an email using SmtpClient?

Manas Bhardwaj7-Sep-09 9:27

7-Sep-09 9:27

jrahma wrote:
before proceeding to send an email using SmtpClient

You can not!!!

Manas Bhardwaj
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Jassim Rahma7-Sep-09 9:32

7-Sep-09 9:32

so you mean there is not way to send whatever call or (ping!) to the email to verify if the email was correct or it's just a fake email?

Manas Bhardwaj7-Sep-09 9:34

7-Sep-09 9:34

Untill and unless you do not send the email, you can not.
But, why would you do this? This is usually done by spammers to get hold of actual email addresses D'Oh! | :doh:

Manas Bhardwaj
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Jassim Rahma7-Sep-09 9:39

7-Sep-09 9:39

because I have a feedback form and I want to make sure the email was correct in order to reply yo the user and to avoid people sending me junk emails using fake addresses..

so what's the solution?

Pete O'Hanlon7-Sep-09 9:45

Pete O'Hanlon

7-Sep-09 9:45

jrahma wrote:
so what's the solution?

If you can come up with a reliable method to do this, you'll become very, very rich. There's currently no foolproof way to do this.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

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Not Active7-Sep-09 9:48

Not Active

7-Sep-09 9:48

As he has been saying there is no way to verify an email address is valid unless you send a message. Most applications rely on the user to provide a correct email and warn them if the email is not correct they will not get any messages.

Other ways to eliminate potential fake emails is to send a confirmation and only active the email if the user responds. You can remove any email addresses that have not been responded to in a certain time period.

only two letters away from being an asset

DaveyM697-Sep-09 9:51

DaveyM69

7-Sep-09 9:51

IIRC (it was a long time ago) the best I was ever able to come up with was to validate the email address with regex and do a look up for the MX records of the domain of the email address.

This won't ensure the email address exists - daveym69[at]microsoft.com would pass (don't want spam bots hitting MS mail servers hence the [at]!), but at least you know it's properly formed and the domain actually has a mail server.

Dave

Generic BackgroundWorker - My latest article!
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Why are you using VB6? Do you hate yourself? (Christian Graus)

MarkB7777-Sep-09 18:07

MarkB777

7-Sep-09 18:07

Hi there,

Have a look into CAPTCHA's.

If you don't like this, another option to add a hidden textbox. Spam bots will generally fill in every box on the page (hidden or not) and then submit the form.

All you have to do is check that the hidden box is empty - if not, it is a non-human user.

Cheers,

Mark Brock
"We're definitely not going to make a G or a PG version of this. It's not PillowfightCraft." -- Chris Metzen

0x3c07-Sep-09 9:55

0x3c0

7-Sep-09 9:55

I might be mistaken, but I think there's something in the SMTP protocol which allows this. If you're feeling particularly masochistic you could implement this. I think it works in a similar way to POP - that is, text based requests and responses.

OSDev

new line is not showing

Jassim Rahma7-Sep-09 9:18

7-Sep-09 9:18

I am using this code to send an email using MailMessage:

msg.Body = txtMessage.Text;

but it's all coming as one paragraph without the line breaks though I have enter key between every paragraph?

how can I fix this in Windows Application?

Manas Bhardwaj7-Sep-09 9:25

7-Sep-09 9:25

You should use the IsBodyHtml property like this:

mail.Body = "first line<br/>next line";
 mail.IsBodyHtml = True

Manas Bhardwaj
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Jassim Rahma7-Sep-09 9:29

7-Sep-09 9:29

it is set to true.. but it's still not considering the ENTER key and it's all coming as one paragraph!

msg.Subject = subject;
msg.Body = message;
msg.IsBodyHtml = true;

Manas Bhardwaj7-Sep-09 9:32

7-Sep-09 9:32

jrahma wrote:
but it's still not considering the ENTER k

And it will not. ENTER key is /r/n which is not html. The mail message expects the body message to be valid html else it gets confused.

Can you try this:

msg.Subject = subject;
message = message.Replace(@"\r\n", "<br/>");
msg.Body = message;
msg.IsBodyHtml = true;

Manas Bhardwaj
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Jassim Rahma7-Sep-09 9:37

7-Sep-09 9:37

I tried but it's still the same.. here is the code:

msg.Subject = subject;
message = message.Replace(@"\r\n", "");
msg.Body = message;
msg.IsBodyHtml = true;

Manas Bhardwaj7-Sep-09 9:48

7-Sep-09 9:48

jrahma wrote:
I tried but it's still the same.. here is the code:

Ah!!! the text editor screwed the code Frown | :(

msg.Subject = subject;
message = message.Replace(@"\r\n", "<br/>");
msg.Body = message;
msg.IsBodyHtml = true;

Can you try the above?

Manas Bhardwaj
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check for update

Jassim Rahma7-Sep-09 8:48

7-Sep-09 8:48

i want to know what's the best way to check for new version of my C# windows application while the application starts?

Not Active7-Sep-09 9:51

Not Active

7-Sep-09 9:51

You can use Click Once[^] deployment.

only two letters away from being an asset

Christian Graus7-Sep-09 11:54

Christian Graus

7-Sep-09 11:54

I am planning on writing a webservice that let's my app do this, and download updates. Clickonce has it's issues, not least that the programs don't end up in program files.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Jassim Rahma8-Sep-09 4:27

8-Sep-09 4:27

can you share it in an article plz so we can also learn from it?

Jassim Rahma10-Sep-09 10:10

10-Sep-09 10:10

if I am going to use XML file to check the version, can I use Windows Live SkyDrive?

sending SMS

Jassim Rahma7-Sep-09 8:26