Only accept integers in a text box with linked spin button

Hi All,

I have a linked text box and spin button on a userform so the user can enter text or use the buttons and I'm having trouble barring non-integer inputs! Here's what I have so far:

Text box = NumberBox
Spin button= NumberSpin

Private Sub NumberBox_Change()

If IsNumeric(Me.NumberBox.Text) Then
Me.NumberSpin.Value = Me.NumberBox.Text
ElseIf Me.NumberBox.Text = "" Then
Me.NumberSpin.Value = False
Else
    MsgBox "Qty must be a whole number"
    Me.NumberBox.Text = prevvalue
    

End If
End Sub


Private Sub NumberSpin_Change()

If IsNumeric(Me.NumberBox.Text) Or Me.NumberBox.Text = "" Then
    Me.NumberBox.Text = Me.NumberSpin.Value
    Else
    prevvalue = Me.NumberBox.Text
End If

End Sub

Any help would be greatly appreciated. Thanks!