'Primer 24: Formular za konverziju valute (dinar/evro) 
Option Explicit

Private Sub m_btnKonverzijaDuE_Click()
    If m_optProdajni.Value Then
        If proveraPolja(m_txtDinari.Text, m_txtProdajni.Text) Then
            m_txtEvri.Text = Format(m_txtDinari.Text / m_txtProdajni.Text, ".##")
        End If
    Else
        If proveraPolja(m_txtDinari.Text, m_txtKupovni.Text) Then
            m_txtEvri.Text = Format(m_txtDinari.Text / m_txtKupovni.Text, ".##")
        End If
    End If
End Sub

Private Sub m_btnKonverzijaEuD_Click()
    If m_optProdajni.Value Then
        If proveraPolja(m_txtEvri.Text, m_txtProdajni.Text) Then
            m_txtDinari.Text = Format(m_txtEvri.Text * m_txtProdajni.Text, ".##")
        End If
    Else
        If proveraPolja(m_txtEvri.Text, m_txtKupovni.Text) Then
             m_txtDinari.Text = Format(m_txtEvri.Text * m_txtKupovni.Text, ".##")
        End If
    End If

End Sub

Function proveraPolja(polje1 As String, polje2 As String) As Boolean
    If polje1 = "" Or polje2 = "" Then
        MsgBox "Niste popunuli sva neophodna polja formulara"
        proveraPolja = False
    Else
        proveraPolja = True
    End If
End Function