Private Sub cmdDown_MouseDown(Button As Integer, Shift As _
    Integer, X As Single, Y As Single)
    m_Increment = -1
    tmrNumber.Enabled = True
End Sub

Private Sub cmdDown_MouseUp(Button As Integer, Shift As _
    Integer, X As Single, Y As Single)
    tmrNumber.Enabled = False
End Sub

Private Sub cmdUp_MouseDown(Button As Integer, Shift As _
    Integer, X As Single, Y As Single)
    m_Increment = 1
    tmrNumber.Enabled = True
End Sub

Private Sub cmdUp_MouseUp(Button As Integer, Shift As _
    Integer, X As Single, Y As Single)
    tmrNumber.Enabled = False
End Sub

Private Sub tmrNumber_Timer()
Const MIN_NUMBER = -100
Const MAX_NUMBER = 100

    m_Number = m_Number + m_Increment
    If m_Number < MIN_NUMBER Then
        m_Number = MIN_NUMBER
    ElseIf m_Number > MAX_NUMBER Then
        m_Number = MAX_NUMBER
    End If

    txtNumber.Text = Format$(m_Number)
End Sub