Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents Label1 As System.Windows.Forms.Label
    Friend WithEvents Label2 As System.Windows.Forms.Label
    Friend WithEvents LstDVDs As System.Windows.Forms.ListBox
    Friend WithEvents GroupBox1 As System.Windows.Forms.GroupBox
    Friend WithEvents Label3 As System.Windows.Forms.Label
    Friend WithEvents TxtDVD As System.Windows.Forms.TextBox
    Friend WithEvents TxtPrice As System.Windows.Forms.TextBox
    Friend WithEvents Label4 As System.Windows.Forms.Label
    Friend WithEvents TxtTax As System.Windows.Forms.TextBox
    Friend WithEvents Label5 As System.Windows.Forms.Label
    Friend WithEvents txtTotal As System.Windows.Forms.TextBox
    Friend WithEvents Label6 As System.Windows.Forms.Label
    Friend WithEvents BtnPay As System.Windows.Forms.Button
    Friend WithEvents BtnClear As System.Windows.Forms.Button
    Friend WithEvents BtnQuit As System.Windows.Forms.Button
    Friend WithEvents BtnSum As System.Windows.Forms.Button
    Friend WithEvents LstTotals As System.Windows.Forms.ListBox
    Friend WithEvents Label7 As System.Windows.Forms.Label
    Friend WithEvents Label8 As System.Windows.Forms.Label
    Friend WithEvents LstMovies As System.Windows.Forms.ListBox
    Friend WithEvents Grpresults As System.Windows.Forms.GroupBox
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.Label1 = New System.Windows.Forms.Label
        Me.LstDVDs = New System.Windows.Forms.ListBox
        Me.Label2 = New System.Windows.Forms.Label
        Me.GroupBox1 = New System.Windows.Forms.GroupBox
        Me.BtnQuit = New System.Windows.Forms.Button
        Me.BtnClear = New System.Windows.Forms.Button
        Me.BtnPay = New System.Windows.Forms.Button
        Me.txtTotal = New System.Windows.Forms.TextBox
        Me.Label6 = New System.Windows.Forms.Label
        Me.TxtTax = New System.Windows.Forms.TextBox
        Me.Label5 = New System.Windows.Forms.Label
        Me.TxtPrice = New System.Windows.Forms.TextBox
        Me.Label4 = New System.Windows.Forms.Label
        Me.TxtDVD = New System.Windows.Forms.TextBox
        Me.Label3 = New System.Windows.Forms.Label
        Me.BtnSum = New System.Windows.Forms.Button
        Me.Grpresults = New System.Windows.Forms.GroupBox
        Me.LstTotals = New System.Windows.Forms.ListBox
        Me.LstMovies = New System.Windows.Forms.ListBox
        Me.Label7 = New System.Windows.Forms.Label
        Me.Label8 = New System.Windows.Forms.Label
        Me.GroupBox1.SuspendLayout()
        Me.Grpresults.SuspendLayout()
        Me.SuspendLayout()
        '
        'Label1
        '
        Me.Label1.AutoSize = True
        Me.Label1.Font = New System.Drawing.Font("Microsoft Sans Serif", 18.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label1.Location = New System.Drawing.Point(296, 8)
        Me.Label1.Name = "Label1"
        Me.Label1.Size = New System.Drawing.Size(173, 37)
        Me.Label1.TabIndex = 0
        Me.Label1.Text = "DVDs R Us"
        '
        'LstDVDs
        '
        Me.LstDVDs.ItemHeight = 16
        Me.LstDVDs.Location = New System.Drawing.Point(40, 80)
        Me.LstDVDs.Name = "LstDVDs"
        Me.LstDVDs.Size = New System.Drawing.Size(312, 180)
        Me.LstDVDs.TabIndex = 1
        '
        'Label2
        '
        Me.Label2.Font = New System.Drawing.Font("Microsoft Sans Serif", 10.2!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label2.Location = New System.Drawing.Point(32, 48)
        Me.Label2.Name = "Label2"
        Me.Label2.Size = New System.Drawing.Size(240, 32)
        Me.Label2.TabIndex = 2
        Me.Label2.Text = "Choose DVD:"
        '
        'GroupBox1
        '
        Me.GroupBox1.Controls.Add(Me.BtnQuit)
        Me.GroupBox1.Controls.Add(Me.BtnClear)
        Me.GroupBox1.Controls.Add(Me.BtnPay)
        Me.GroupBox1.Controls.Add(Me.txtTotal)
        Me.GroupBox1.Controls.Add(Me.Label6)
        Me.GroupBox1.Controls.Add(Me.TxtTax)
        Me.GroupBox1.Controls.Add(Me.Label5)
        Me.GroupBox1.Controls.Add(Me.TxtPrice)
        Me.GroupBox1.Controls.Add(Me.Label4)
        Me.GroupBox1.Controls.Add(Me.TxtDVD)
        Me.GroupBox1.Controls.Add(Me.Label3)
        Me.GroupBox1.Location = New System.Drawing.Point(408, 56)
        Me.GroupBox1.Name = "GroupBox1"
        Me.GroupBox1.Size = New System.Drawing.Size(352, 352)
        Me.GroupBox1.TabIndex = 3
        Me.GroupBox1.TabStop = False
        Me.GroupBox1.Text = "Purchase Info"
        '
        'BtnQuit
        '
        Me.BtnQuit.Location = New System.Drawing.Point(240, 240)
        Me.BtnQuit.Name = "BtnQuit"
        Me.BtnQuit.Size = New System.Drawing.Size(96, 40)
        Me.BtnQuit.TabIndex = 10
        Me.BtnQuit.Text = "Quit"
        '
        'BtnClear
        '
        Me.BtnClear.Location = New System.Drawing.Point(128, 240)
        Me.BtnClear.Name = "BtnClear"
        Me.BtnClear.Size = New System.Drawing.Size(96, 40)
        Me.BtnClear.TabIndex = 9
        Me.BtnClear.Text = "Clear"
        '
        'BtnPay
        '
        Me.BtnPay.Location = New System.Drawing.Point(16, 240)
        Me.BtnPay.Name = "BtnPay"
        Me.BtnPay.Size = New System.Drawing.Size(96, 40)
        Me.BtnPay.TabIndex = 8
        Me.BtnPay.Text = "Pay"
        '
        'txtTotal
        '
        Me.txtTotal.Location = New System.Drawing.Point(136, 176)
        Me.txtTotal.Name = "txtTotal"
        Me.txtTotal.ReadOnly = True
        Me.txtTotal.Size = New System.Drawing.Size(192, 22)
        Me.txtTotal.TabIndex = 7
        Me.txtTotal.Text = ""
        '
        'Label6
        '
        Me.Label6.Font = New System.Drawing.Font("Microsoft Sans Serif", 10.2!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label6.Location = New System.Drawing.Point(16, 176)
        Me.Label6.Name = "Label6"
        Me.Label6.Size = New System.Drawing.Size(136, 32)
        Me.Label6.TabIndex = 6
        Me.Label6.Text = "Total:"
        '
        'TxtTax
        '
        Me.TxtTax.Location = New System.Drawing.Point(136, 128)
        Me.TxtTax.Name = "TxtTax"
        Me.TxtTax.ReadOnly = True
        Me.TxtTax.Size = New System.Drawing.Size(192, 22)
        Me.TxtTax.TabIndex = 5
        Me.TxtTax.Text = ""
        '
        'Label5
        '
        Me.Label5.Font = New System.Drawing.Font("Microsoft Sans Serif", 10.2!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label5.Location = New System.Drawing.Point(16, 128)
        Me.Label5.Name = "Label5"
        Me.Label5.Size = New System.Drawing.Size(136, 32)
        Me.Label5.TabIndex = 4
        Me.Label5.Text = "Tax:"
        '
        'TxtPrice
        '
        Me.TxtPrice.Location = New System.Drawing.Point(136, 80)
        Me.TxtPrice.Name = "TxtPrice"
        Me.TxtPrice.ReadOnly = True
        Me.TxtPrice.Size = New System.Drawing.Size(192, 22)
        Me.TxtPrice.TabIndex = 3
        Me.TxtPrice.Text = ""
        '
        'Label4
        '
        Me.Label4.Font = New System.Drawing.Font("Microsoft Sans Serif", 10.2!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label4.Location = New System.Drawing.Point(16, 80)
        Me.Label4.Name = "Label4"
        Me.Label4.Size = New System.Drawing.Size(136, 32)
        Me.Label4.TabIndex = 2
        Me.Label4.Text = "DVD Price:"
        '
        'TxtDVD
        '
        Me.TxtDVD.Location = New System.Drawing.Point(136, 40)
        Me.TxtDVD.Name = "TxtDVD"
        Me.TxtDVD.ReadOnly = True
        Me.TxtDVD.Size = New System.Drawing.Size(192, 22)
        Me.TxtDVD.TabIndex = 1
        Me.TxtDVD.Text = ""
        '
        'Label3
        '
        Me.Label3.Font = New System.Drawing.Font("Microsoft Sans Serif", 10.2!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label3.Location = New System.Drawing.Point(16, 40)
        Me.Label3.Name = "Label3"
        Me.Label3.Size = New System.Drawing.Size(136, 32)
        Me.Label3.TabIndex = 0
        Me.Label3.Text = "DVD Name:"
        '
        'BtnSum
        '
        Me.BtnSum.Location = New System.Drawing.Point(40, 272)
        Me.BtnSum.Name = "BtnSum"
        Me.BtnSum.Size = New System.Drawing.Size(88, 40)
        Me.BtnSum.TabIndex = 4
        Me.BtnSum.Text = "Show Summary"
        '
        'Grpresults
        '
        Me.Grpresults.Controls.Add(Me.Label8)
        Me.Grpresults.Controls.Add(Me.Label7)
        Me.Grpresults.Controls.Add(Me.LstMovies)
        Me.Grpresults.Controls.Add(Me.LstTotals)
        Me.Grpresults.Location = New System.Drawing.Point(32, 328)
        Me.Grpresults.Name = "Grpresults"
        Me.Grpresults.Size = New System.Drawing.Size(360, 280)
        Me.Grpresults.TabIndex = 5
        Me.Grpresults.TabStop = False
        Me.Grpresults.Text = "Summary of Sales"
        Me.Grpresults.Visible = False
        '
        'LstTotals
        '
        Me.LstTotals.ItemHeight = 16
        Me.LstTotals.Location = New System.Drawing.Point(224, 40)
        Me.LstTotals.Name = "LstTotals"
        Me.LstTotals.Size = New System.Drawing.Size(88, 228)
        Me.LstTotals.TabIndex = 0
        '
        'LstMovies
        '
        Me.LstMovies.ItemHeight = 16
        Me.LstMovies.Location = New System.Drawing.Point(16, 40)
        Me.LstMovies.Name = "LstMovies"
        Me.LstMovies.Size = New System.Drawing.Size(192, 228)
        Me.LstMovies.TabIndex = 1
        '
        'Label7
        '
        Me.Label7.Font = New System.Drawing.Font("Microsoft Sans Serif", 10.2!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label7.Location = New System.Drawing.Point(40, 16)
        Me.Label7.Name = "Label7"
        Me.Label7.Size = New System.Drawing.Size(144, 16)
        Me.Label7.TabIndex = 2
        Me.Label7.Text = "Movie"
        '
        'Label8
        '
        Me.Label8.Font = New System.Drawing.Font("Microsoft Sans Serif", 10.2!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label8.Location = New System.Drawing.Point(224, 16)
        Me.Label8.Name = "Label8"
        Me.Label8.Size = New System.Drawing.Size(120, 16)
        Me.Label8.TabIndex = 3
        Me.Label8.Text = "Number Sold"
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 15)
        Me.ClientSize = New System.Drawing.Size(824, 624)
        Me.Controls.Add(Me.Grpresults)
        Me.Controls.Add(Me.BtnSum)
        Me.Controls.Add(Me.GroupBox1)
        Me.Controls.Add(Me.Label2)
        Me.Controls.Add(Me.LstDVDs)
        Me.Controls.Add(Me.Label1)
        Me.Name = "Form1"
        Me.Text = "DVDs R Us"
        Me.GroupBox1.ResumeLayout(False)
        Me.Grpresults.ResumeLayout(False)
        Me.ResumeLayout(False)

    End Sub

#End Region

    Dim inpf As IO.StreamReader
    Dim outf As IO.StreamWriter
    Const taxRate As Double = 0.07
    ' declare arrays - need it to be bigger than would ever need it
    Dim totals(1000) As Integer
    Dim movies(1000) As String
    Dim numDVDs As Integer
    Dim currDVD As Integer



    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim nextDVD As String
        ' load list box from file
        If IO.File.Exists("DVDs.txt") Then
            ' file exists, loop until end of file
            inpf = IO.File.OpenText("DVDs.txt")
            Do While inpf.Peek() <> -1
                nextDVD = inpf.ReadLine()
                LstDVDs.Items.Add(nextDVD)
                ' pull movie name out of line read and stick in array for safekeeping
                Dim commapos As Integer = nextDVD.IndexOf(","c)
                ' pull out movie title from before comma
                movies(numDVDs) = nextDVD.Substring(0, commapos)
                ' update number of dvds
                numDVDs = numDVDs + 1
            Loop
            inpf.Close()

        Else
            MsgBox("Sorry, list of DVDs not found. Please create a file named DVDs.txt in the bin folder")
            Me.Close()
        End If
    End Sub

    Private Sub LstDVDs_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LstDVDs.SelectedIndexChanged
        Dim strLine As String
        strLine = LstDVDs.SelectedItem
        currDVD = LstDVDs.SelectedIndex  ' keep track of which item selected - in global variable so buy handler knows index number
        strLine = strLine.Trim
        Dim movie As String
        Dim price As Double
        Dim tax As Double
        Dim total As Double
        ' find where in line the comma is
        Dim commapos As Integer = strLine.IndexOf(","c)
        ' pull out movie title from before comma
        movie = strLine.Substring(0, commapos)
        ' pull out price from after comma
        price = Convert.ToDouble(strLine.Substring(commapos + 1).Trim())
        'MsgBox(movie & " selected - cost is: " & price)
        TxtDVD.Text = movie
        TxtPrice.Text = price.ToString("c")
        tax = price * taxRate
        TxtTax.Text = tax.ToString("c")
        total = price + tax
        txtTotal.Text = total.ToString("c")
    End Sub

    Private Sub BtnQuit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnQuit.Click
        Me.Close()

    End Sub

    Private Sub BtnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnClear.Click
        TxtDVD.Text = ""
        TxtPrice.Text = ""
        TxtTax.Text = ""
        txtTotal.Text = ""
    End Sub

    Private Sub BtnPay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnPay.Click
        MsgBox("In real system, this would proceed to form for payment - e.g. handle credit card")

        ' establish output file
        outf = IO.File.AppendText("sales.txt")
        outf.WriteLine(" " & TxtDVD.Text & ", " & TxtPrice.Text & ", " & _
            TxtTax.Text & ", " & txtTotal.Text)
        outf.Close()
        ' update count of sales for the movie
        totals(currDVD) = totals(currDVD) + 1

    End Sub

    Private Sub BtnSum_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnSum.Click
        Dim mov As Integer
        ' first clear out any previous results
        LstMovies.Items.Clear()
        LstTotals.Items.Clear()

        For mov = 0 To numDVDs - 1
            LstMovies.Items.Add(movies(mov))
            LstTotals.Items.Add(totals(mov))
        Next mov
        ' make the info visible
        Grpresults.Visible = True
    End Sub
End Class