One way
Option Explicit
Sub test()
Dim s1 As String, s2 As String
s1 = "asdf" & vbCrLf & "asdf"
s2 = vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf & vbCrLf
If ContainsReqularChars(s1) Then
MsgBox "Some regular chars"
Else
MsgBox "Nothing but non-regular chars"
End If
If ContainsReqularChars(s2) Then
MsgBox "Some regular chars"
Else
MsgBox "Nothing but non-regular chars"
End If
End Sub
Private Function ContainsReqularChars(s As String) As Boolean
Dim s1 As String
s1 = Replace(s, vbCr, vbNullString)
s1 = Replace(s1, vbLf, vbNullString)
s1 = Replace(s1, vbTab, vbNullString)
s1 = Replace(s1, vbBack, vbNullString)
ContainsReqularChars = (Len(s1) > 0)
End Function