'Programmer: Janet Joy
'List manager program with menu
Public Class Form1
    Dim currentFile As String
    Dim changed As Boolean = False
    Private Sub ExitToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles mnuExit.Click
        'Temporary: we will addcheck for save later
        End
    End Sub

    Private Sub mnuInsert_Click(sender As Object, e As EventArgs) Handles mnuInsert.Click
        'Add an item to the list box
        Dim s As String
        s = InputBox("Enter item", "Add Item")
        If s <> "" Then
            ListBox1.Items.Add(s)
            changed = True
        End If
    End Sub

    Private Sub mnuDelete_Click(sender As Object, e As EventArgs) Handles mnuDelete.Click
        'Delete if there are items and one is selected
        If ListBox1.Items.Count > 0 And ListBox1.SelectedIndex >= 0 Then
            ListBox1.Items.RemoveAt(ListBox1.SelectedIndex)
            changed = True
        Else
            ListBox1.Text = ""
        End If
        If ListBox1.Items.Count > 0 Then
            ListBox1.SelectedIndex = 0
        End If
    End Sub
    Private Sub SaveList()
        Dim S As String
        Dim Num As Integer
        If currentFile = "" Then
            SaveFileDialog1.ShowDialog()
            currentFile = SaveFileDialog1.FileName
        End If
        If currentFile <> "" Then
            FileOpen(1, currentFile, OpenMode.Output)
            For Num = 0 To ListBox1.Items.Count - 1
                S = ListBox1.Items.Item(Num)
                PrintLine(1, S)
            Next Num
            FileClose(1)
            MsgBox("Items saved: " & ListBox1.Items.Count)
        End If
    End Sub 'SaveList

    Private Sub mnuSave_Click(sender As Object, e As EventArgs) Handles mnuSave.Click
        SaveList()
        changed = False
    End Sub

    Private Sub mnuOpen_Click(sender As Object, e As EventArgs) Handles mnuOpen.Click
        'Opens selected file and adds to list box if not changed or user doesn't want to save
        Dim oktoClear As Boolean = True 'this will be the value if there has been no change
        If changed Then
            oktoClear = AskToSave()
        End If
        If oktoClear Then
            ListBox1.Items.Clear()
            If OpenFileDialog1.ShowDialog() = DialogResult.OK Then
                currentFile = OpenFileDialog1.FileName
                Dim S As String = ""
                Me.Text = currentFile
                FileOpen(1, currentFile, OpenMode.Input) 'open the file for input
                While Not EOF(1) 'EOF=End of file, this loops to read all recordds
                    S = LineInput(1) 'read from file 1
                    Me.ListBox1.Items.Add(S) 'add the item read to the combo box
                End While
                FileClose(1) 'close file 1
                If Me.ListBox1.Items.Count > 0 Then 'make sure the file was read
                    Me.ListBox1.SelectedIndex = 0
                End If
                changed = False
            End If
        End If
    End Sub
    Private Function AskToSave() As Boolean
        Dim Answer As MsgBoxResult
        Dim okToClear As Boolean = False 'will be the return value
        If Changed Then
            Answer = MsgBox("Do you want to save?",
            MsgBoxStyle.YesNoCancel + MsgBoxStyle.Question, "Save")
            If Answer = MsgBoxResult.Yes Then
                SaveList()
                okToClear = True
            End If
            If Answer = MsgBoxResult.No Then
                okToClear = True 'clear the list box without saving
            End If
            If Answer = MsgBoxResult.Cancel Then
                okToClear = False
            End If
        End If
        'if changed is false, then false is returned
        Return okToClear
    End Function 'AskToSave

    Private Sub mnuNew_Click(sender As Object, e As EventArgs) Handles mnuNew.Click
        'Start a new list if not changed or user doesn't want to save
        Dim canClear As Boolean = True
        If changed Then canClear = AskToSave()
        If canClear = True Then
            ListBox1.Items.Clear()
            currentFile = ""
            changed = False
        End If
    End Sub
End Class