Validating regular expression

If you actually check the Google query I linked above, people have been writing (or trying to write) RFC-compliant regular expressions to parse email addresses for years.

But what if I told you there were a way to determine whether or not an email is valid without resorting to regular expressions at all? The activation email is a practice that’s been in use for years, but it’s often paired with complex validations that the email is formatted correctly.

To validate input captured with server controls, you can use the Regular Expression Validator control. Input validation can become a security issue if an attacker discovers that you have made unfounded assumptions.

To validate other forms of input, such as query strings, cookies, and HTML control input, you can use the System. The attacker can then supply carefully crafted input that compromises your application by attempting SQL injection, cross-site scripting, and other injection attacks.

It is provided as a courtesy for individuals who are still using these technologies.

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Duncan Mackenzie Microsoft Developer Network May 2002 Summary: Covers the basics of inheriting from another control and adding your own properties, methods, and events along with adding your own code; one of a series of Microsoft Windows Forms control development samples to be read in conjunction with associated overview article. This article is the second in a five-article series on developing controls in Microsoft® .

To avoid such vulnerability, you should validate text fields (such as names, addresses, tax identification numbers, and so on) and use regular expressions to do the following: Regular expression support is available to ASP. If you capture input by using server controls, you can use the Regular Expression Validator control to validate that input.

NET applications through the Regular Expression Validator control and the Regex class in the System. You can use regular expressions to restrict the range of valid characters, to strip unwanted characters, and to perform length and format checks.

This How To shows how you can use regular expressions within ASP. Regular expressions are a good way to validate text fields such as names, addresses, phone numbers, and other user information.

You can use them to constrain input, apply formatting rules, and check lengths. This How To shows how you can use regular expressions within ASP. Objectives Overview Using a Regular Expression Validator Control Using the Regex Class Common Regular Expressions Additional Resources If you make unfounded assumptions about the type, length, format, or range of input, your application is unlikely to be robust.

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