inventory program containing read and write to txt file

Option Strict On
Imports System.IO

Public Class OderEntryForm1

    'Structure to hold product record info.

    Structure ProductRecord

        'to hold product name.

        Dim strProduct As String

        'to hold quantity on hand.

        Dim strQuantity As String

        'to hold price.

        Dim strPrice As String

        '******************************************************************************

        'This procedure uses an array to list items in the list box.

        '******************************************************************************

        Dim lstProducts As ListBox

lstProducts.Items.Add= ("A45", "B24", "C12", "D78", "E45")

    End Structure

    '******************************************************************************

    'This procedure reads data from a text file into an array of the ProductRecord

    ' structure.  It then writes out the array data to an output text file.

    '******************************************************************************

    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs)

        'declare variables for the input text file.

        Dim textFileIn As StreamReader

        'declare variables for the output text file.

        Dim textFileOut As StreamWriter

        'declare variables for the input and output file names.

        Dim strFileTextIn As String

        Dim strFileTextOut As String

     
   'declare a variable of the structure ProductRecord.

        Dim productRecord(5) As ProductRecord

        Dim intIndex As Integer

        Dim sngPrice As Single

        Dim sngQuantity As Single

        Dim intCount As Integer


        'assign the input data file.

        strFileTextIn = "Textfile.txt"

        'test for existence of input data file.

        If File.Exists(strFileTextIn) Then

            'open the data file for input.

            textFileIn = File.OpenText(strFileTextIn)

            'initialize array index.

            intIndex = 0
            'test for end of input data file.

            Do Until textFileIn.Peek = -1

                'read fields from input data file into array of ProductRecord.

                With textFileIn

                    productRecord(intIndex).strProduct = .ReadLine()

                    productRecord(intIndex).strQuantity = .ReadLine()

                    productRecord(intIndex).strPrice = .ReadLine()

                    'assign price field to a price variable.

                    sngPrice = CSng(productRecord(intIndex).strPrice)

                    'calculate a price.

                    sngPrice = CSng(sngPrice * sngQuantity)

                    'assign the price to the price field in the ProductRecord array.

                    productRecord(intIndex).strPrice = CStr(sngPrice)

                End With

                'increment the array index.

                intIndex += 1

            Loop

            'close the input data file.

            textFileIn.Close()


            'assign the output data file.

            strFileTextOut = "Textfile.txt"

            'create the data file for ouput.

            textFileOut = File.CreateText(strFileTextOut)

            'create or open existing file for appending new records.

            textFileOut = File.AppendText(strFileTextOut)

            'calculate the number of records read from file.

            intCount = intIndex - 2

            'write records to output data file.

            For intIndex = 0 To intCount

                MsgBox(productRecord(intIndex).strProduct)


                textFileOut.WriteLine(productRecord(intIndex).strProduct)

                textFileOut.WriteLine(productRecord(intIndex).strPrice)

                textFileOut.WriteLine(productRecord(intIndex).strQuantity)

            Next

            'close the output data file to write any remaining records to file.

            textFileOut.Close()

        Else

            MsgBox("File does not exist.")

        End If

    End Sub

    Private Sub lblPrice_Click(sender As System.Object, e As System.EventArgs)

    End Sub

    Private Sub lstProducts_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles lstProducts.SelectedIndexChanged

    End Sub
End Class