Public Class Form1
    Dim Changed As Boolean = False
    Dim Canceled As Boolean = False

    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) _
      Handles Me.FormClosing
        Canceled = False
        AskToSave()
        If Canceled Then e.Cancel = True 'Program does NOT end!
    End Sub 'Form1_FormClosing
    Private Sub Form1_Load(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles MyBase.Load
        Dim S As String = ""
        FileOpen(1, "C:\todo.txt", OpenMode.Input)
        While Not EOF(1)
            S = LineInput(1)
            Me.CboTodo.Items.Add(S)
        End While
        FileClose(1)
        If Me.CboTodo.Items.Count > 0 Then
            Me.CboTodo.SelectedIndex = 0
        End If
    End Sub 'Form1_Load
    Public Sub AddItem()
        Dim Item As String
        Dim P As Integer
        Item = InputBox("Task to add:", "Add")
        If Item <> "" Then
            P = Me.CboTodo.FindString(Item) 'is item already in box?
            If P = -1 Then 'add if not there already
                Me.CboTodo.Items.Add(Item)
                P = Me.CboTodo.FindString(Item)
            End If
            Me.CboTodo.SelectedIndex = P 'display added item
            Changed = True
        End If
    End Sub 'AddItem

    Private Sub MnuAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MnuAdd.Click
        AddItem()
    End Sub 'MnuAdd_Click

    Private Sub MnuSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) _
         Handles MnuSave.Click
        SaveList()
    End Sub 'mnuSave_Click

    Private Sub SaveList()
        Dim S As String
        Dim Num As Integer
        FileOpen(1, "C:\todo.txt", OpenMode.Output)
        For Num = 0 To Me.CboTodo.Items.Count - 1
            S = Me.CboTodo.Items.Item(Num)
            PrintLine(1, S)
        Next Num
        FileClose(1)
        MsgBox("Items saved: " & Me.CboTodo.Items.Count)
        Changed = False
    End Sub 'SaveList
    Private Sub mnuDelete_Click(ByVal sender As Object, ByVal e As System.EventArgs) _
      Handles MnuDelete.Click
        DeleteItem()
    End Sub 'mnuDelete_Click

    Private Sub DeleteItem()
        If Me.CboTodo.Items.Count > 0 Then
            Me.CboTodo.Items.RemoveAt(Me.CboTodo.SelectedIndex)
        Else
            Me.CboTodo.Text = ""
        End If
        If Me.CboTodo.Items.Count > 0 Then
            Me.CboTodo.SelectedIndex = 0
        End If
        Changed = True
    End Sub 'DeleteItem
    Private Sub mnuExit_Click(ByVal sender As Object, ByVal e As System.EventArgs) _
          Handles MnuExit.Click
        AskToSave()
    End Sub 'mnuExit_Click

    Private Sub AskToSave()
        Dim Answer As MsgBoxResult
        If Changed Then
            Answer = MsgBox("Do you want to save?", _
              MsgBoxStyle.YesNoCancel + MsgBoxStyle.Question, "Save")
            If Answer = MsgBoxResult.Yes Then
                SaveList()
                End
            End If
            If Answer = MsgBoxResult.No Then
                End 'end the program
            End If
            If Answer = MsgBoxResult.Cancel Then
                Canceled = True
            End If
            'Do NOT end if they cancel!
        Else
            End 'end the program if no changes
        End If
    End Sub 'AskToSave
End Class