Sub Invoice(ByRef Name As String, ByVal address As String, ByVal zip As String, ByVal chairs As Double, ByVal sofas As Double)
        Dim Invoice As String, SofaPrice, ChairPrice, Tax As Double
        Dim sr As IO.StreamReader = IO.File.OpenText("PRICE_TAXDATA.TXT")
        Dim fmtstr As String = "{0,-8}|{1,10}"
        Dim basePrice, total As Double
        Invoice = InvoiceNum(Name, zip)
        ChairPrice = CDbl(sr.ReadLine)
        SofaPrice = CDbl(sr.ReadLine)
        Tax = CDbl(sr.ReadLine)
        basePrice = (ChairPrice * chairs) + (SofaPrice * sofas)
        total = (basePrice * Tax) + basePrice
        lstDisplay.Items.Add("Invoice Number: " & InvoiceNum(Name, zip))
        lstDisplay.Items.Add("")
        lstDisplay.Items.Add("Name: " & NameSwitch(Name))
        lstDisplay.Items.Add("Address: " & address)
        lstDisplay.Items.Add("City: " & zip)
        lstDisplay.Items.Add("")
        lstDisplay.Items.Add("Number of chairs: " & chairs)
        lstDisplay.Items.Add("Number of sofas: " & sofas)
        lstDisplay.Items.Add("")
        lstDisplay.Items.Add(fmtstr, "Cost:", basePrice)
        lstDisplay.Items.Add(fmtstr, "Sales Tax:"(basePrice * Tax))
        lstDisplay.Items.Add(fmtstr, " ", "------------")
        lstDisplay.Items.Add(fmtstr, "Total Cost:" & total)
    End Sub