fetch valid email id from database

You can't tell if an email address read from your database is valid or not except by first looking at it and seeing if it conforms to the rules for emails addresses[^] and then sending it an email and seeing if you get a response.

Even a "good looking" email address (in the sense that it is well formed and conforms to the rules for such addresses) such as xxx@xxx.xxx can be sent to, but it is not a "valid" email address in that there is either a message box at the other end, or a human being to read it if there was. The only way to tell is to send an email and see if you get a response - if you do, it is a valid email address at that moment.

That does not mean it is a valid email address immediately after you have received the response - there are places which provide valid email addresses which last a total of ten minutes for example.

Dear by the following method you can get your work done

1. Read all email-ID in a datatable

2. use the following method to check ifthe email is valid

//suppose datatable name is dt

if(dt.Rows[0]["Email"].toString().indexOf("@")>0) 
{

string emailPart=dt.Rows[0]["Email"].toString().SubString(dt.Rows[0]["Email"].toString().indexOf("@"),dt.Rows[0]["Email"].toString().Length-dt.Rows[0]["Email"].toString().indexOf("@"));

if(emailPart.IndexOf(".")>0)
{

//display the email in your textBox
}
}

I guess it solves your problem. Do let me know if it dosen't