Using SelectionSort with a Listbox for Visual Basic

[ramayes7314]

Hello,

I am starting out with Visual Basic, and I am trying to learn how to implement selectionsort with visual basic.

This is my code.

Option Strict On

Public Class Form1

    'Project    SelectionSort
    'Purpose    Sort and count the number of exchanges and comparisons which the algorithm performs. 
    'Input      None
    'Output     None

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCount.Click

        'Purpose    Count the number of exchanges.
        'Input      None
        'Output     None

        Dim min As Integer          'Variable min 

        Dim min_index As Integer    'Index of variable min

        Dim last_index As Integer   'Index of last

        last_index = Listbox1.Items.Count - 1
        min = CInt(Listbox1.Items(0))
        min_index = 0

        For J = 1 To last_index
            If min > CInt(Listbox1.Items(J)) Then
                min = CInt(Listbox1.Items(J))
                min_index = J

            End If
        Next

        lblCount.Text = CStr(min_index)

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRandomize.Click

        'Purpose    Randomize the numbers in the listbox.
        'Input      None
        'Output     None

        Dim J As Integer        'Loop control variable

        'Clear the listbox
        Listbox1.Items.Clear()

        'Generate a list of random numbers between 0 and 1
        Randomize()
        For J = 1 To 100
            Listbox1.Items.Add(Rnd())
        Next

    End Sub

    Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSort.Click

        'Purpose    Selectionsort
        'Input      None    
        'Output     None
        'Error      There is an error with this part of the program. I believe that one of these conversions is not correct. Everything else seems to be running smoothly as it not giving me a build error but a logic error.

        Dim i As Integer        'Loop control variable for min to max
        Dim j As Integer        'Loop control variable for i + 1 to max
        Dim best_value As Long  'Best value in listbox
        Dim best_j As Integer   'Best j value from the listbox
        Dim min As Integer      'Min value in list
        Dim max As Integer      'Max value in list

        For i = min To max - 1
            best_value = CInt(Listbox1.Items(i))
            best_j = i
            For j = i + 1 To max
                If CInt(Listbox1.Items(j)) < best_value Then
                    best_value = CInt(Listbox1.Items((j)))
                    best_j = j
                End If
            Next j
            Listbox1.Items(best_j) = Listbox1.Items(i)
            Listbox1.Items(i) = best_value
        Next i

    End Sub

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

        'Purpose    Terminates the program
        'Input      Click
        'Output     Closes program

        Close()
    End Sub
End Class

I have highlighted the area that I am having trouble with. I would like someone to work with me, so that I can figure out what I am doing wrong.

[Hack]

Moved From The CodeBank (which is for sharing code rather than posting questions )

You posted this in the VB6 Codebank, but it is clear from your example code that you are not using that version, but, rather, VB.NET

What version of VB.NET are you using? 2008? 2010? 2012? Earlier?

[dunfiddlin]

There is a better way to sort ListBox Items

Dim lb(ListBox1.Items.Count - 1) As Object ' set up array of appropriate dimension
        ListBox1.Items.CopyTo(lb, 0) ' copy to the array
        Array.Sort(lb) ' use the generic array sort (ascending)
        Array.Reverse(lb) ' use reverse to create descending sort
        ListBox1.Items.Clear()
        ListBox1.Items.AddRange(lb) ' copy items back

[ramayes7314]

Thank you Hack for moving my post. I am using VB 2010.

Thank you, that code works. However, I kind of wanted to figure out how to use selectionsort to complete this program before moving on to other sorting codes.

[ramayes7314]

Thank you Hack!

I am using Visual Basic 2010.

That method works. However, I am trying to learn selectionsort for a project that I am doing.
Also, what sorting method is that called.