The ending quotation mark must not be preceded by a backslash character (\).
If the first character is a quotation mark, match a beginning quotation mark followed by at least one occurrence of any character, followed by an ending quotation mark.
A complex regex validation on the email address doesn’t introduce an additional solution, it introduces an additional problem.
find out if a user has entered a valid email address?
The email’s domain name must start with “A-Za-z0-9-“, follow by first level Tld (.com, .net) “.[A-Za-z0-9]” and optional follow by a second level Tld (au, my) “\.[A-Za-z]”, where second level Tld must start with a dot “.” and length must equal or more than 2 characters.
Think about it this way: I register for your website under the email address . That’s probably going to bounce off of the illustrious mail daemon, but the formatting is fine; it’s a valid email address.
To fix this problem, you implement an activation system where, after registering, I am sent an email with a link I must click.
This pattern can be repeated one or more times, and must be followed by the top-level domain name. To include them in a regular expression library, either copy and paste the code into a Visual Studio Class Library project, or copy and paste it into a text file and compile it from the command line with a command like the following (assuming that the name of the source code file is Regex or Regex Utilities.vb: You can also use the Regex.
If the character that follows @ is not an opening bracket, match one alphanumeric character with a value of A-Z, a-z, or 0-9, followed by zero or more occurrences of a hyphen, followed by zero or one alphanumeric character with a value of A-Z, a-z, or 0-9, followed by a period. To determine whether an email address is valid, pass the email address to the Mail Address. methods can be included in a library of regular expression utility methods, or they can be included as private static or instance methods in the application class.