Imports System.IO

Public Class frmPart3

    Private Sub frmPart3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Call ReadMyFile()
    End Sub

    Private Sub btnLoad_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLoad.Click
        Call ReadMyFile()
    End Sub

    Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
        If Trim(txtNew.Text) <> "" Then
            lbItems.Items.Add(txtNew.Text)
            txtNew.Text = ""
        End If
    End Sub

    Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
        Call UpdateMyFile()
    End Sub

    Private Sub ReadMyFile()

        Dim InBuf As Integer
        Dim dataFile As String

        '---trap any File I/O errors
        Try


            InBuf = FreeFile()
            FileOpen(InBuf, "a:\storeitems.txt", OpenMode.Input)

            Do Until EOF(InBuf)
                dataFile = LineInput(InBuf)  'read in an entire line using lineinput
                lbItems.Items.Add(dataFile)  'add the item just read into the listbox
            Loop

            FileClose(InBuf)

        Catch Err As IOException

            MessageBox.Show(Err.Message, "I cannot Read the File")
            Me.Close()
            End
        Finally
            FileClose(InBuf)
        End Try

    End Sub

    Private Sub UpdateMyFile()
        Dim OutBuf As Integer
        Dim x As Integer

        OutBuf = FreeFile()

        '---trap any File I/O errors
        Try

            OutBuf = FreeFile()
            FileOpen(OutBuf, "a:\storeitems.txt", OpenMode.Output)

            '---loop through the list of items in ListBox and write each item to 
            '   the sequential file.

            '---count holds total number of items but is zero based
            '   so we subtract 1.  First item in ListBox is 0 not 1 so start the loop at 0.
            '   Count must be less 1 because I use x to count the loop and also identify the actual item.
            'If I new there we only/always 4 items, I could use  For x = 0 to 3.

            '---EXAMPLE:
            '   Index         Item          Count
            '   0               apples          1
            '   1               oranges        2   
            '   2               tires             3   
            '   3               boxes           4

            For x = 0 To lbItems.Items.Count - 1
                PrintLine(OutBuf, lbItems.Items(x))
            Next

            FileClose(OutBuf)

        Catch Err As IOException
            MessageBox.Show(Err.Message, "I cannot access the File")
            Me.Close()
            End
        Finally
            FileClose(OutBuf)
        End Try

    End Sub

   
End Class