Private Sub Form_Click()
Dim s As String, i As Integer, n As Integer
s = InputBox("input your str...", , "abCDEf")
For i = 1 To Len(s)
Select Case (Mid(s, i, 1))
Case "a" To "z"
n = n + 1
End Select
Next
MsgBox "character:" & n
End Sub
a~z的ASCII为97~122,比对就好了