Validating Email

While doing some coding the other day I needed an expression to validate email addresses. The trick was that it had to be flexible enough to handle emails in the format of username@company.com and firstname.lastname@company.com.

Imports System.Text.RegularExpressions

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim strEmail As String = "thom.robbins@microsoft.com"

        Dim regexp As New Regex("^([\w-]+\.)*?[\w-]+@[\w-]+\.([\w-]+\.)*?[\w]+$")

        If regexp.IsMatch(strEmail) Then

            MsgBox("Valid Email")

        Else

            MsgBox("Invalid Email")

        End If

End Sub

Comments

• Anonymous
  August 23, 2004
  The left-hand-side of your regexp needs tightening up -- As it currently stands, it would fail with valid email addresses like rodbegbie+example@gmail.com.
  
  If you look at RFC-2822 you'll see all the (legitimate) characters you can include in the local part of an email address.