[RESOLVED] Checking text box for @ symbol

[AdRock952]

Can anyone please tell me how i check a text box for the @ symbol?

I have a text box that an email address is to be entered and I want to check that the user is entering a valid email address, not just some random text.

I am pretty sure I could use Instr but i've only ever used it once and i didn't really understand it

[Piller]

If InStr(Text1.Text, "@") > 0 Then
    'code
End If

InStr returns a number if its there if not its 0. This checks to see if it returns a value greater then zero.

[Joacim Andersson]

Yes you should use InStr. It returns the position of where it has found one string in another... which of course could be 0 if the string is not found.

Dim nPos As Long
nPos = InStr(Text1.Text, "@")
If nPos Then
    MsgBox "@-symbol found at position " & nPos
End If

[MartinLiss]

Can anyone please tell me how i check a text box for the @ symbol?

I have a text box that an email address is to be entered and I want to check that the user is entering a valid email address, not just some random text.

I am pretty sure I could use Instr but i've only ever used it once and i didn't really understand it

This thread among others that I found when I did an Advanced Search for validate email might help you.

[Hack]

Try this from Karl Moore

Private Function IsEMailAddress(ByVal sEmail As String, Optional ByRef sReason As String) As Boolean
 'code by Karl Moore
 
    Dim sPreffix As String
    Dim sSuffix As String
    Dim sMiddle As String
    Dim nCharacter As Integer
    Dim sBuffer As String
 
    sEmail = Trim(sEmail)
 
    If Len(sEmail) < 8 Then
        IsEMailAddress = False
        sReason = "Too short"
        Exit Function
    End If
 
 
    If InStr(sEmail, "@") = 0 Then
        IsEMailAddress = False
        sReason = "Missing the @"
        Exit Function
    End If
 
 
    If InStr(InStr(sEmail, "@") + 1, sEmail, "@") <> 0 Then
        IsEMailAddress = False
        sReason = "Too many @"
        Exit Function
    End If
 
 
    If InStr(sEmail, ".") = 0 Then
        IsEMailAddress = False
        sReason = "Missing the period"
        Exit Function
    End If
 
    If InStr(sEmail, "@") = 1 Or InStr(sEmail, "@") = Len(sEmail) Or _
        InStr(sEmail, ".") = 1 Or InStr(sEmail, ".") = Len(sEmail) Then
        IsEMailAddress = False
        sReason = "Invalid format"
    Exit Function
 
End If
 
 
For nCharacter = 1 To Len(sEmail)
    sBuffer = Mid$(sEmail, nCharacter, 1)
    If Not (LCase(sBuffer) Like "[a-z]" Or sBuffer = "@" Or _
    sBuffer = "." Or sBuffer = "-" Or sBuffer = "_" Or _
    IsNumeric(sBuffer)) Then: IsEMailAddress = _
    False: sReason = "Invalid character": Exit Function
Next nCharacter
 
nCharacter = 0
 
On Error Resume Next
 
sBuffer = Right(sEmail, 4)
If InStr(sBuffer, ".") = 0 Then GoTo TooLong:
If Left(sBuffer, 1) = "." Then sBuffer = Right(sBuffer, 3)
If Left(Right(sBuffer, 3), 1) = "." Then sBuffer = Right(sBuffer, 2)
If Left(Right(sBuffer, 2), 1) = "." Then sBuffer = Right(sBuffer, 1)
 
 
If Len(sBuffer) < 2 Then
    IsEMailAddress = False
    sReason = "Suffix too short"
    Exit Function
End If
 
TooLong:
 
If Len(sBuffer) > 3 Then
    IsEMailAddress = False
    sReason = "Suffix too long"
    Exit Function
End If
 
sReason = Empty
IsEMailAddress = True
 
End Function
 
Private Sub Command1_Click()
Dim IsValid As Boolean
Dim InvalidReason As String
IsValid = IsEMailAddress(Text1.Text, InvalidReason)
If IsValid = True Then
   MsgBox "Valid EMail address format"
Else
   MsgBox "Invalid format, the reason given is: " & InvalidReason
End If
End Sub