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[zachman61]

I'm trying to check if a string contains letters because I need a numerical only string, anyone know how to check if it contains letters?

[comathi]

Code: Select all

Dim containsLetter As Boolean
        For i = 0 To s.Length - 1
            If Asc(s.Substring(i, 1)) < 48 Or Asc(s.Substring(i, 1)) > 57 Then containsLetter = True
        Next
        If containsLetter Then MessageBox.Show("The string must contain numbers only!")

You can replace s by the name of your string, and the messagebox is optionnal.

This uses ASCII character codes to determine whether or not the String contains something other than numbers (anything not between 48 and 57, basically).

[Cheatmasterbw]

you can also use the isNumeric function:

Code: Select all

if isNumeric(StringVariable) then
...
end if

[Shim]

function

Code: Select all

Function CheckForAlphaCharacters(ByVal StringToCheck As String)


    For i = 0 To StringToCheck.Length - 1
        If Char.IsLetter(StringToCheck.Chars(i)) Then
            Return True
        End If
    Next

    Return False

End Function

usage

Code: Select all

 Dim Mystring As String = "abc123"
    If CheckForAlphaCharacters(Mystring) Then
        'do stuff here if it contains letters
    Else
        'do stuff here if it doesn't contain letters
    End If

##credits stackoverflow

[zachman61]

Thanks, I spent like 30-40 minutes googling but stack overflow didn't popup.