Variables are used before it is assigned a null value. Using StreamReader - vb.net

Question

I decided to try one of the advanced exercises in my book, it needs me to edit a program. Before getting the artist name and price, the btn.Add_Click procedure should determine whether the CD name is already included in the list box. If the list box contains the CD name, the procedure should display an appropriate message and then not add the CD to the list. Problem is the Do Until inFile.Peek = -1 and the For Each Name As String In strNameCollection apparently are assigned a null value. Any ideas on why this is or possibly how to get this to work? btn.Add_Click is towards the bottom of the code
Option Explicit On
Option Strict On
Option Infer Off
Public Class frmMain
Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
Me.Close()
End Sub
Private Sub frmMain_FormClosing(sender As Object, e As Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
' save the list box information
' declare a StreamWriter variable
Dim outFile As IO.StreamWriter
' open the file for output
outFile = IO.File.CreateText("CDs.txt")
' write each line in the list box
For intIndex As Integer = 0 To lstCds.Items.Count - 1
outFile.WriteLine(lstCds.Items(intIndex))
Next intIndex
' close the file
outFile.Close()
End Sub
Private Sub frmMain_Load(sender As Object, e As EventArgs) Handles Me.Load
' fills the list box with data
' stored in a sequential access file
' declare variables
Dim inFile As IO.StreamReader
Dim strInfo As String
' verify that the file exists
If IO.File.Exists("CDs.txt") Then
' open the file for input
inFile = IO.File.OpenText("CDs.txt")
' process loop instructions until end of file
Do Until inFile.Peek = -1
strInfo = inFile.ReadLine
lstCds.Items.Add(strInfo)
Loop
inFile.Close()
' select the first line in the list box
lstCds.SelectedIndex = 0
Else
MessageBox.Show("Can't find the CDs.txt file",
"CD Collection",
MessageBoxButtons.OK,
MessageBoxIcon.Information)
End If
End Sub
Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
' adds CD information to the list box
' declare variables
Dim strName As String
Dim strArtist As String
Dim strPrice As String
Dim strConcatenatedInfo As String
Dim dblPrice As Double
Dim strNameCollection() As String
'read all names into array
Dim inFile As IO.StreamReader
If IO.File.Exists("CDs.txt") Then
' open the file for input
inFile = IO.File.OpenText("CDs.txt")
End If
'read all names into array
Dim index As Integer = 0
Do Until inFile.Peek = -1
ReDim strNameCollection(index)
strNameCollection(index) = inFile.ReadLine
Loop
inFile.Close()
' get the CD information
strName = InputBox("CD name:", "CD Collection")
For Each Name As String In strNameCollection
If strName = Name Then
MessageBox.Show("Sorry that name was alread on the list", "CD Project",
MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
Else
strArtist = InputBox("Artist:", "CD Collection")
strPrice = InputBox("Price:", "CD Collection")
Double.TryParse(strPrice, dblPrice)
strPrice = dblPrice.ToString("N2")
strConcatenatedInfo = strName.PadRight(40) &
strArtist.PadRight(25) & strPrice.PadLeft(5)
lstCds.Items.Add(strConcatenatedInfo)
End If
Next Name
End Sub
Private Sub btnRemove_Click(sender As Object, e As EventArgs) Handles btnRemove.Click
' removes the selected line from the list box
' if a line is selected, remove the line
If lstCds.SelectedIndex <> -1 Then
lstCds.Items.RemoveAt(lstCds.SelectedIndex)
End If
End Sub
End Class

Answer 1

Why not take advantage of the Using blocks? Make strNameCollection a List(Of String) instead of an array that you are not increasing it's size correctly.
Private strNameCollection As New List(Of String)
Using sr As New StreamReader("CDs.txt")
While Not sr.EndOfStream
strNameCollection.Add(sr.ReadLine)
End while
End Using ' file closed and stream disposed