Reading from text file and storing into an array

[public]

Hi, I am given a problem where I have a text file that contains the following:

12AVX
5
23ABC
8.97
23TWT
4.69
34ZAB
12.5
91BAN
34.67

Some of the instructions include "Define a structure named Product. The structure should contain two member variables: a String variable to store the item number and a Double variable to store the price" and "Declare a class-level array that contains five Product structure variables."

I am stuck on the following "The form’s Load event procedure should read the item numbers and prices from the ItemInfo.txt fi le and store them in the classlevel array. It also should add the item numbers to the list box."

Option Explicit On
Option Strict On
Option Infer Off

Public Class frmMain

    Private ProductInfo(4) As Product

    Structure Product
        Public strId As String
        Public dblPrice As Double
    End Structure

    Private Sub btnExit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnExit.Click
        Me.Close()
    End Sub

    Private Sub frmMain_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim inFile As IO.StreamReader
        Dim intArray As Integer
        Dim intLength As Integer
        Dim strTemp As String

        ' verify that the file exists
        If IO.File.Exists("ItemInfo.txt") = True Then
            ' open the file for input
            inFile = IO.File.OpenText("ItemInfo.txt")
            'process loop instructions until end of

            Do Until inFile.Peek = -1
                strTemp = inFile.ReadLine
                Integer.TryParse(strTemp, intLength)

                If intLength = 5 Then
                    ProductInfo(intArray).strId = strTemp
                Else
                    Double.TryParse(strTemp, ProductInfo(intArray).dblPrice)
                End If

                ' add the line to the list box
                lstNumbers.Items.Add(ProductInfo(intArray).strId)

                intArray = intArray + 1
            Loop

            ' close the file
            inFile.Close()

            ' select the first line in the list box
            lstNumbers.SelectedIndex = 0

        End If
    End Sub
End Class

When I run this code my list box is empty and I am not sure where I went wrong. Any help would be appreciated.

[.paul.]

try this:

Public Class Form1
 
    ''' <summary>
    ''' Product Structure
    ''' </summary>
    ''' <remarks>contains a string member + a double member.
    ''' overriding the ToString, determines what is displayed in the listbox when you add a Product</remarks>
    Private Structure Product
        Dim itemNumber As String
        Dim price As Double
        Public Overrides Function ToString() As String
            Return Me.itemNumber
        End Function
    End Structure
    ''' <summary>
    ''' products array
    ''' </summary>
    ''' <remarks>5 element array of Product</remarks>
    Dim products(4) As Product
 
    ''' <summary>
    ''' Form1_Load event
    ''' </summary>
    ''' <param name="sender"></param>
    ''' <param name="e"></param>
    ''' <remarks>here we read the text file, then loop through the lines + load the products array + add products to listbox</remarks>
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim lines() As String = IO.File.ReadAllLines("fileName.txt")
 
        Dim counter As Integer = 0
 
        For x As Integer = 0 To lines.GetUpperBound(0) Step 2
            products(counter).itemNumber = lines(x)
            products(counter).price = CDbl(lines(x + 1))
            ListBox1.Items.Add(products(counter))
            counter += 1
        Next
 
    End Sub
 
    ''' <summary>
    ''' ListBox1_SelectedIndexChanged event
    ''' </summary>
    ''' <param name="sender"></param>
    ''' <param name="e"></param>
    ''' <remarks>this shows how you can use the ListBox.SelectedItem</remarks>
    Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
        Label1.Text = DirectCast(ListBox1.SelectedItem, Product).price.ToString("c2")
    End Sub
 
End Class

[cheowkwen]

.paul.'s code should works fine..