Problems with getting contents from Readline() into Arrays

[Ima290]

For the most part, my program is working fine, but this procedure is given me issues when used

http://pastie.org/3950400 .. I've messed around quite a bit with it and I can't seem to get it to work.. it either freezes the program or spits out an error like:

>{"Index was outside the bounds of the array."}

> System.IndexOutOfRangeException

> Index was outside the bounds of the array.


If I change line 38 to something like (40) from (-1) the program will just hang and eventually an error will pop up because it hasn't responded.

Thanks in advance.

[dday9]

Take a look at this explination on arrays. The next section in the tutorial explains the outside the bounds error you're getting.

[Ima290]

Thanks for the post, but I'm just unable to see where abouts I'm getting that code.. everything looks good to me. the -1 should be working I would have thought.. if I try any large value (the text tile only has up to 30 lines) it just hangs and freezes the program.

Thanks.

[dday9]

I'm not going to open your project with the link provided. I would post the code wraped in 'code' tags. Because right now I'm only speculating what's up.

Edit - Post the code where you use the array, not the whole project :P

[Ima290]

'Variable used to locate the requested title by the user.
        Dim strRequestedBook As String = InputBox("Please enter the title of the requested book", "Information Needed")
 
        'This will create an array which will be used to store each line from the textfile into. This will be used to process and find the required book
        Dim strResultArray(99) As String
        Dim intResultArrayIndex As Integer = 0
 
        While readDetails.Peek() >= 0
            strResultArray(intResultArrayIndex) = readDetails.ReadLine()
            intResultArrayIndex += 1
        End While
 
        readDetails.Close()
 
 
        Dim intSearchforTitleIndex As Integer = 0
        'This loop will then iterate over the array values near the title value and then store those back into the text boxes
        Do While intSearchforTitleIndex < strResultArray.Length - 1
            If strResultArray(intSearchforTitleIndex) <> strRequestedBook Then
                intSearchforTitleIndex += 1
            ElseIf intSearchforTitleIndex >= strResultArray.Length - 1 Then
                MessageBox.Show("Sorry, that book was not found in that text file. Please try again", "Title not found")
                If MsgBoxResult.Cancel Then Return
            Else
                txtTitle.Text = strResultArray(intSearchforTitleIndex)
                txtBookID.Text = strResultArray(intSearchforTitleIndex + 1)
                txtAuthorOne.Text = strResultArray(intSearchforTitleIndex + 2)
                txtAuthorTwo.Text = strResultArray(intSearchforTitleIndex + 3)
                txtAuthorThree.Text = strResultArray(intSearchforTitleIndex + 4)
                txtPublisher.Text = strResultArray(intSearchforTitleIndex + 5)
                txtYearPublished.Text = strResultArray(intSearchforTitleIndex + 6)
                txtBuyingPrice.Text = strResultArray(intSearchforTitleIndex + 7)
                txtSellingPrice.Text = strResultArray(intSearchforTitleIndex + 8)
                txtCopyNumber.Text = strResultArray(intSearchforTitleIndex + 9)
 
                If strResultArray(intSearchforTitleIndex + 10) = "True" Then
                    clbGenres.SetItemChecked(0, True)
                ElseIf strResultArray(intSearchforTitleIndex + 11) = "True" Then
                    clbGenres.SetItemChecked(1, True)
                ElseIf strResultArray(intSearchforTitleIndex + 12) = "True" Then
                    clbGenres.SetItemChecked(2, True)
                ElseIf strResultArray(intSearchforTitleIndex + 13) = "True" Then
                    clbGenres.SetItemChecked(3, True)
                ElseIf strResultArray(intSearchforTitleIndex + 14) = "True" Then
                    clbGenres.SetItemChecked(4, True)
                ElseIf strResultArray(intSearchforTitleIndex + 15) = "True" Then
                    clbGenres.SetItemChecked(5, True)
                ElseIf strResultArray(intSearchforTitleIndex + 16) = "True" Then
                    clbGenres.SetItemChecked(6, True)
                ElseIf strResultArray(intSearchforTitleIndex + 17) = "True" Then
                    clbGenres.SetItemChecked(7, True)
                ElseIf strResultArray(intSearchforTitleIndex + 18) = "True" Then
                    clbGenres.SetItemChecked(8, True)
                ElseIf strResultArray(intSearchforTitleIndex + 19) = "True" Then
                    clbGenres.SetItemChecked(9, True)
                End If
 
            End If
        Loop
 
    End Sub

That's the relevant part of it.

[kareninstructor]

Hello,

Is this a school project?
Is it possible to change the structure of the text file?

Seems that if you have control over the text file a delimited version would be better meaning each line is a record rather than spread the record across multiple lines.

[DataMiser]

Is there a reason you are not using the readalllines() method? This would simplify your code quite a lot.

[Ima290]

Hello,

Is this a school project?
Is it possible to change the structure of the text file?

Seems that if you have control over the text file a delimited version would be better meaning each line is a record rather than spread the record across multiple lines.

Yeah it is. I could change the structure, but I don't know how to better implement it. The code is a mess, I've been learning quite a few of the functions/methods as I've been going along, so a lot of it is stuff I've never used before now, which has left it a bit of a mess.

Is there a reason you are not using the readalllines() method? This would simplify your code quite a lot.

How could I implement that?

[DataMiser]

Dim fLines() As String = System.IO.File.ReadAllLines("c:\MyFile.Txt")

This would populate an array with the lines from the file specified.

[Ima290]

Dim fLines() As String = System.IO.File.ReadAllLines("c:\MyFile.Txt")

This would populate an array with the lines from the file specified.

Thanks, I'd adjusted it so it's now:

Dim strReadDetails() As String
        Dim openFileDialog As New OpenFileDialog
        clearall()
 
        'Check to see if user would like to use last .txt file used to save info
        If fileSaveDialog.FileName <> "" Then
            Dim msgResponse As MsgBoxResult
            MessageBox.Show("Would you like to use the previously used file?", "Access most recent text file", MessageBoxButtons.YesNo)
            If msgResponse <> MsgBoxResult.Yes Then
                strReadDetails = File.ReadAllLines(openFileDialog.FileName)
            Else
                openFileDialog.Filter = "Text Documents|*.txt"
                openFileDialog.Title = "Please locate the file you wish to open"
                openFileDialog.ShowDialog()
                Try
                    strReadDetails = File.ReadAllLines(openFileDialog.FileName)
                Catch exFatalError As Exception
                    Return
                End Try
            End If
        Else
            openFileDialog.Filter = "Text Documents|*.txt"
            openFileDialog.Title = "Please locate the file which contains the requested information"
            openFileDialog.ShowDialog()
            Try
                strReadDetails = File.ReadAllLines(openFileDialog.FileName)
            Catch exFatalError As Exception
                Return
            End Try
        End If

If I enter a word in the file, it causes the program to hang. If I enter a word not in the file, nothing at all happens (I'm assuming the exception handler is causing the last bit).

Here's the full code for the procedure -

http://pastebin.com/sShYzPu8

Thanks

[kareninstructor]

There are a lot of methods to read a text file into a container, search for information and present information but if you are at a learning stage for a school assignment you are better off learning the basics rather than using the best method available.

The example below reads a text file into an array of type Book (which does not have the same information as you have as I am not here to do your homework so if you want to use this then modify as needed). The text file is structured for one record per line.

Text file (Books.txt) resides in the same folder as the executable. You can of course use a OpenDialog to make this dynamic.

1,Book1,Author1,12.99
2,Book2,Author1,5.50
3,Book3,Author2,20.99

Note the first column would be our identifier to the record while the remaining columns contain data we are after.

A simple class (place in a class module) to remember data from the text file.

Public Class Book
    Public Property Identifier As Integer
    Public Property Name As String
    Public Property Author As String
    Public Property SellingPrice As Decimal
    Public Sub New(ByVal Identifier As Integer, ByVal BookName As String, ByVal Author As String, ByVal SellingPrice As Decimal)
        Me.Identifier = Identifier
        Me.Name = BookName
        Me.Author = Author
        Me.SellingPrice = SellingPrice
    End Sub
    Public Sub New()
    End Sub
    Public Overrides Function ToString() As String
        Return String.Format("ID: [{0}] Book: [{1}] Author: [{2}] Selling Price [{3}] ", Me.Identifier, Me.Name, Me.Author, Me.SellingPrice)
    End Function
End Class

Form code to work the data, TextBox controls begin with txt and button begin with cmd.

Public Class frmMainForm
    ''' <summary>
    ''' Oversize our array, will be shorten later with ReDim
    ''' </summary>
    ''' <remarks></remarks>
    Private BookArray(100) As Book
    Private FileName As String = IO.Path.Combine(Application.StartupPath, "Books.txt")
    Private Sub frmMainForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        LoadTextFile()
    End Sub
    Private Sub LoadTextFile()
        Dim BookData As String() = {}
        Dim Reader As New IO.StreamReader(FileName)
        Dim Line As String = ""
        Dim Index As Integer = 0

        Do
            Line = Reader.ReadLine()
            If Not Line Is Nothing Then
                BookData = Line.Split(","c)
                BookArray(Index) = New Book(CInt(BookData(0)), BookData(1), BookData(2), CDec(BookData(3)))
                Index += 1
            End If
        Loop Until Line Is Nothing

        Reader.Close()

        ReDim Preserve BookArray(Index)

    End Sub
    Private Sub cmdSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSearch.Click

        If txtRequestedBook.Text.Length > 0 Then

            Dim FoundBook As Book = Nothing

            For x As Integer = 0 To BookArray.GetUpperBound(0) - 1
                '
                ' Case insensitive search
                '
                If BookArray(x).Name.ToLower = txtRequestedBook.Text.ToLower Then
                    FoundBook = BookArray(x)
                    Exit For
                End If
            Next

            If FoundBook IsNot Nothing Then
                txtBookID.Text = FoundBook.Identifier.ToString
                txtBook.Text = FoundBook.Name
                '
                ' Shows ToString method of Book class
                '
                'MessageBox.Show(FoundBook.ToString)
                '
                '
                '
            Else
                txtBookID.Text = ""
                txtBook.Text = ""
                MessageBox.Show(txtRequestedBook.Text & " was not located.")
            End If

            ActiveControl = cmdSearch
        Else
            MessageBox.Show("Please enter a book name.")
            ActiveControl = txtRequestedBook
        End If
    End Sub
End Class

The above is very basic with limited exception handling.