Public Class Form1
    ' Numbers Sorting App by Ryan Arnold.
    'Code written with help from John Morgan, Eric Gimbel, RaspBarrySenpai, and TheDuckLord.
    Private Sub txtInput_KeyPress(sender As Object, e As KeyPressEventArgs) Handles txtInput.KeyPress
        ' This prevents the user from entering anything other than an integer from 0 to 9 in the text box.
        If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso e.KeyChar <> ControlChars.Back Then
            e.Handled = True
        End If
    End Sub

    Private Sub btnEnterAmount_Click(sender As Object, e As EventArgs) Handles btnEnterAmount.Click
        ' Make the TextBox Read Only, change the Text properties of btnEnterAmount and lblInstructions, and declare variables needed for adding to the ListBox.
        txtInput.ReadOnly = True
        btnEnterAmount.Text = "Next Number"
        lblInstructions.Text = "Please click 'Next Number'."
        Dim intUserInput As Integer
        Dim intListCount As Integer
        Dim strUserInput2 As String
        Dim intParseVariable As Integer = 0

        ' Convert user input to an Integer, put it into a variable, then make the ListBox count equal to that amount.
        intUserInput = CInt(txtInput.Text)
        intListCount = lstNumberList.Items.Count

        ' Make sure the ListBox Count is equal to the abovementioned variable, then display a MessageBox.
        If intListCount = intUserInput Then
            MessageBox.Show("All set! Please click the Sort List button below.")
            btnEnterAmount.Enabled = False
            ' Otherwise, display an InputBox.
        Else
            strUserInput2 = InputBox("Please enter a number.", "Need Input", , ,)
            ' If the user tries to enter anything besides a number, display a MessageBox.
            If Integer.TryParse(strUserInput2, intParseVariable) Then
                lstNumberList.Items.Add(strUserInput2)
            Else
                MessageBox.Show("Please enter a numeric value.")
                Return
            End If
        End If
        ' Change the text of btnEnterAmount.
        btnEnterAmount.Text = "Next Number"
    End Sub

    Private Sub btnSort_Click(sender As Object, e As EventArgs) Handles btnSort.Click
        ' Declare a variable as a Boolean value
        Dim blnSorted As Boolean
        ' Do Until loop for sorting the numbers in the ListBox
        Do Until blnSorted
            blnSorted = True
            For intCount As Integer = 0 To lstNumberList.Items.Count - 2
                If (lstNumberList.Items(intCount) > lstNumberList.Items(intCount + 1)) Then
                    Dim intTemp As Integer = lstNumberList.Items(intCount)
                    lstNumberList.Items(intCount) = lstNumberList.Items(intCount + 1)
                    lstNumberList.Items(intCount + 1) = intTemp
                    blnSorted = False
                End If
            Next
        Loop
    End Sub

    Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
        ' Exit program when Exit button is clicked.
        Me.Close()
    End Sub
End Class