Public Class frmRechnungErstellung
    Dim EinzelP As Decimal = 0
    Dim Menge As Decimal = 1
    Dim Gesamt As Decimal = 0

    Private Sub frmRechnungErstellung_Load(ByVal sender As System.Object, ByVal _
      e As System.EventArgs) Handles MyBase.Load
        Me.txtEinzelpreis.Text = EinzelP.ToString
        Me.txtMenge.Text = Menge.ToString
        Me.txtGesamt.Text = Gesamt.ToString       
    End Sub

    Private Sub txtEinzelpreis_KeyUp(ByVal sender As System.Object, ByVal e As _
      System.Windows.Forms.KeyEventArgs) Handles txtEinzelpreis.KeyUp
        EinzelP = CDec(txtEinzelpreis.Text)
        Gesamt = EinzelP * Menge
        txtGesamt.Text = Gesamt.ToString("C")
    End Sub
 
    Private Sub txtMenge_KeyUp(ByVal sender As System.Object, ByVal e As _
      System.Windows.Forms.KeyEventArgs) Handles txtMenge.KeyUp
        Menge = CDec(txtMenge.Text)
        Gesamt = EinzelP * Menge
        txtGesamt.Text = Gesamt.ToString("C")
    End Sub