Private Sub btnCompute_Click(ByVal sender As Object, _
        ByVal e As System.EventArgs) Handles btnCompute.Click
 
    Dim arg1, arg2, result As Decimal
 
    'Aufspaltung der Eingabe anhand von Leerzeichen
    Dim parts() As String = txtCompute.Text.Split(" "c)
    If parts.Length <> 3 Then Exit Sub
 
    'Numerische Argumente checken
    If Not Decimal.TryParse(parts(0), arg1) Then Exit Sub
    If Not Decimal.TryParse(parts(2), arg2) Then Exit Sub
 
    'Berechnung durchführen
    Select parts(1)
        Case "+" : result = arg1 + arg2
        Case "-" : result = arg1 - arg2
        Case "*" : result = arg1 * arg2
        Case "/" : result = arg1 / arg2
        Case Else : Exit Sub
    End Select
 
    'Ergebniswert anzeigen  
    txtCompute.Text = CStr(result)
End Sub