How to send a notification to the user that the file is in use by another program

How do you send a notification to the user that the program cannot Autosave a file, while it is in use on another program? It cannot be saved even if there is a timer on the program on the RichTextBox_TextChanged event(). Here is the function:

Code:

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Private Sub AutosaveFile()

        Dim path As String = (My.Computer.FileSystem.SpecialDirectories.Desktop & "\Common-Mistakes-Backup.rtf")
 
            ' This text is added only once to the file.
            If File.Exists(path) = False Then
 
            Using fs As FileStream = File.Create(My.Computer.FileSystem.SpecialDirectories.Desktop & "\Common-Mistakes-Backup.rtf")
                fs.Close()
                ' Save the contents of the RichTextBox into the file.
                RichTextBox1.SaveFile(path, RichTextBoxStreamType.RichText)
                Timer1.Start()

            End Using

            End If
 
        Try
            ' Delete the file if it exists.
            If File.Exists(path) = True Then

                ' Save the contents of the RichTextBox into the file.
                    RichTextBox1.SaveFile(path, RichTextBoxStreamType.RichText)

                    Timer1.Start()

            End If

        Catch ex As Exception
            Console.WriteLine(ex.ToString())
        End Try
 
    End Sub

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Catch the exception and display a MessageBox.

Please clarify these points:
After the comment 'Delete the file... you never delete a file. Is the code incomplete?
What is the purpose of the timer?
As Sitten said, Catch the exception, but make sure to catch the specific exception so you do not lose control of other possible problems.

Because it bothered me so... I boiled down your code down to this:

Code:

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    Private Sub AutosaveFile()

        Dim path As String = (My.Computer.FileSystem.SpecialDirectories.Desktop & "\Common-Mistakes-Backup.rtf")
        Try
            ' Save the contents of the RichTextBox into the file.
            RichTextBox1.SaveFile(path, RichTextBoxStreamType.RichText)
        Catch exInUse As IO.IOException
            MessageBox.Show("Unable to save the file, it is locked by another process.") 'This is where it shouild go for a locked file
        Catch ex As Exception
            Console.WriteLine(ex.ToString())
        End Try

    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        Timer1.Stop()
        AutosaveFile()
        Timer1.Start()

    End Sub

---

I'm not sure why you had it so complicated or what the point of the stream was for... all you needed to do is attempt to save the file, if it fails, you handle it... otherwise you go on. The timer should be stopped & restarted inside the tick event, not the autosave...

-tg

techgnome

Your answer was very good, you write very clean code. Thanks, I have given you a strong reputation.

Sitten Spynne

Good answer too, I had already figured a good way to do that. I have given you a good reputation too!