Private m_Wert1 as double ' (falls es sich um zahlen werte handelt=
Public Property Wert1 as double
    Get
        return m_Wert1
    End Get
    SEt(Value as double)
        m_Wert1 = value
    End set
end property

Pirvate Sub cmdSave(sender...
    m_Wert1 = txtWert1.text
    ....
end Sub

Dim frm as new Formkalulieren
frm.Wert1 = txtWert1
...
if frm.ShowDialog = ok then
    txtWert1.text = frm.Wert1
    ...
endif