Member Avatar for ponnu

I have vb form tht accepts user data.I need to check whether user enters emailid in the correct format ?Please provide suggestion .Thanks in advance

  • 2 Contributors
  • 3 Replies
  • 262 Views
  • 6 Days Discussion Span
  • Latest Post Latest Post by ponnu

Dani AI

Generated

As asked about validating an email while the user types and posted a Like-based VB check, here are a few practical, complementary points and alternatives you can apply depending on whether you’re on classic VB or VB.NET. Two rules to keep in mind: client-side checks are only syntactic (they don't prove the mailbox exists), and overly strict patterns will reject perfectly valid addresses (plus signs, apostrophes, long TLDs, IDNs, etc.).

For VB.NET a simple, reliable syntactic check is to let the framework parse the address with System.Net.Mail.MailAddress. It’s concise and handles many edge cases better than ad-hoc string comparisons:

' VB.NET - syntactic check using System.Net.Mail
Function IsEmailSyntacticallyValid(email As String) As Boolean
    If String.IsNullOrWhiteSpace(email) Then Return False
    email = email.Trim()
    Try
        Dim addr = New System.Net.Mail.MailAddress(email)
        Return True
    Catch ex As FormatException
        Return False
    End Try
End Function

If you need immediate inline feedback (fast client-side test), use a small pragmatic regex rather than an RFC-complete monster. This pattern is simple and practical for most forms:

' Simple, practical regex for inline validation
Imports System.Text.RegularExpressions
Function IsEmailSimpleRegex(email As String) As Boolean
    Dim pattern As String = "^[^@\s]+@[^@\s]+\.[^@\s]+$"
    Return Regex.IsMatch(email.Trim(), pattern, RegexOptions.IgnoreCase)
End Function

UX and troubleshooting tips: validate on the Validating event or on submit (not every keystroke) and show inline errors (ErrorProvider or a small helper text) instead of modal MsgBoxes. Always Trim input, normalize the domain to lower-case, and log examples that fail so you can adjust the pattern. For true verification, send a confirmation email—syntactic checks are only the first step. If you must support internationalized domains, convert them with IdnMapping.GetAscii before validation.

Recommended Answers

All 3 Replies

Member Avatar for rishif2

try this
first define a function

Private Function IsValidEmailAddress(ByVal sEmail As String, Optional ByRef sReason As String) As Boolean
   sEmail = LCase(Trim(sEmail))
   If Len(sEmail) < 7 Then
      sReason = "Too short"
   ElseIf sEmail Like "*[!0-9a-z@._+-]*" Then
      sReason = "Invalid character"
   ElseIf Not sEmail Like "*@*.*" Then
      sReason = "Missing the @ or ."
   ElseIf sEmail Like "*@*@*" Then
      sReason = "Too many @"
   ElseIf sEmail Like "[@.]*" Or sEmail Like "*[@.]" _
      Or sEmail Like "*..*" Or Not sEmail Like "?*@?*.*?" Then
      sReason = "Invalid format"
   Else
      Dim n As Integer
      n = Len(sEmail) - InStrRev(sEmail, ".")
      If n > 3 Then
         sReason = "Suffix too long"
      ElseIf n < 2 Then
         sReason = "Suffix too short"
      Else
         sReason = Empty
         IsValidEmailAddress = True
      End If
   End If
End Function

here call it (Normally On the lostfocus event)

Private Sub Text1_LostFocus()
Dim bool As Boolean, reason As String
bool = IsValidEmailAddress(Me.Text1.Text, reason)
If (bool <> True) Then
MsgBox reason
End If
End Sub

Hope this helps you . . .

Member Avatar for ponnu

its showing error for proper format of email

Member Avatar for ponnu

thank you for resolving :)kindly ignore the former message

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.