Public Class Form1
    Private Structure Car
        Dim model As String
        Dim price As Double
    End Structure

    Private Cars As New Collection

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim sr As New IO.StreamReader("c:\cars.txt")
        Dim tmpCar As Car
        Dim strLine As String
        Do Until sr.EndOfStream

            strLine = sr.ReadLine
            If Not strLine = "" AndAlso Double.TryParse(strLine, 0) = False Then
                tmpCar = New Car
                lstCars.Items.Add(strLine)
                tmpCar.model = strLine
            ElseIf Double.TryParse(strLine, 0) = True Then
                tmpCar.price = Double.Parse(strLine)
                Cars.Add(tmpCar)
            End If
        Loop
    End Sub

    Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
        Dim duration
        Dim amount
        duration = DateRange1.Duration

        If duration > 6 Then
            tmpcar.price = tmpcar.price * 0.8
        End If

        If chkInsurance.Checked Then
            tmpcar.price = tmpcar.price + 10
        End If
        lblPrice.Text = tmpcar.price

    End Sub
End Class