[ETIQUETTE] How to react intelligently on application shutdown.

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  12 years ago

  by konikula

  Matej Kasper

  Trutnov, Czech Republic

  Joined 15 years ago

   Hi. I have few Ideas how to behave when user closes form and material is edited. Example is from my text editor and has few innovations. Just enough to read comments.

   

    Private Sub Form1_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
      Dim s As String = Me.Paper.Text
      If s <> Nothing AndAlso Len(s) > 0 Then 'If text is empty don't ask, simply shutdown
        If FilePath <> Nothing Then
          If IO.File.Exists(FilePath) Then
            If ReadF(FilePath) = s Then 'If text and file opened are identical simply shutdown
              Exit Sub
            End If
          End If
        End If
        'Text and file are different, offer user to forget changes, save them somehow, or cancel shutdown
        Select Case MsgBox("You have unsaved work opened. Save it?", MsgBoxStyle.YesNoCancel, "Warning")
          Case MsgBoxResult.Yes 'User vishes to save work
            If FilePath <> Nothing Then 'If we are editing some file
              If IO.File.Exists(FilePath) Then
                If lFile.rw.FileSize(FilePath, -1) = 0 Then
                  WriteF(FilePath, s) 'If opened file is empty and text is full, ovw auto
                ElseIf lFile.rw.StartsWith(s, FilePath, False) Then
                  WriteF(FilePath, s) 'If opened file is older version of text ovw
                Else
                  Select Case (New dlgFileExists).ShowDialog 'Offer Save,Append,Save As and cancel
                    Case DialogResult.OK : WriteF(FilePath, s)
                    Case DialogResult.Yes : AppendF(FilePath, s)
                    Case DialogResult.Abort
                      fmiSaveAs.PerformClick()
                      'If in saveas was submitted selectfiledialog[sfd] (and file saved)
                      'FilePath was filled with path
                      'no filepath indices cancel of sfd so rather ask to really shutdown application
                      If FilePath = Nothing Then CancelExitPrompt(e)
                      Exit Sub
                    Case DialogResult.Cancel 'this is second place for slower user to cancel saving changes
                      CancelExitPrompt(e) 'so rather ask to continue shutdown
                      Exit Sub
                  End Select
                End If
              Else 'file vanished while editing, for possible reasons of such operation
                fmiSaveAs.PerformClick() 'rather offer Save As instead Save
                If FilePath = Nothing Then CancelExitPrompt(e)
              End If
            Else 'no file was edited, so this is classical time to offer SaveAs
              fmiSaveAs.PerformClick()
              If FilePath = Nothing Then CancelExitPrompt(e)
            End If
          Case MsgBoxResult.Cancel 'For first "Shutdown-modified dialog" it is normal to cancel shutdown on cancel
            e.Cancel = True
        End Select
      End If
    End Sub
  

  
  
  
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