Re: CD-RW help - Visual Basic Discussion Boards

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Re: Filter Empty arrays.

Eddy Vluggen9-Nov-09 7:24

Eddy Vluggen

9-Nov-09 7:24

You can write a query in LINQ to filter the array;

Sub Main()
    Dim myItems As Object() = {10, 20, 30, "", ""}

    Dim myNonEmptyItems = _
        From n In myItems _
        Where (n.GetType().ToString() <> "System.String") _
        Select n

    For Each item In myNonEmptyItems
        Console.WriteLine("Item: " & item.ToString())
    Next

    Console.ReadKey()
End Sub

Enjoy

I are Troll Suspicious | :suss:

File Synchronization/Backup

RichardBerry9-Nov-09 4:34

RichardBerry

9-Nov-09 4:34

I would like to create a small app to synchronize/backup various groups of files or folders between a flashdrive, home pc and work pc.

Any comments to ensure good speed and reliability regarding the following would be appreciated:

1) To determine which files have changed,
<pre>
Dim di As New DirectoryInfo(Path)
Dim files As FileSystemInfo() = di.GetFiles
Dim fi As FileInfo
'Loop through files and see when last modified, and add to a datatable
            For Each fi In files
                        dr = dtFiles.NewRow
                        dr.Item(0) = diNext.Name
                        dr.Item(1) = dr.Item(0) = diNext.LastWriteTime
                        dtFiles.Rows.Add(dr)
         Next

</pre>
Is this OK, or would it be better to check CRC of the files to find the ones that have changed?
I was thinking more along the lines of determining which is the NEWEST file, and then making the sync Bi-Directional though

2) Once I have found the files that are newer, then use:

<pre>System.IO.File.Copy("Sourcefile", "DestinationFile")</pre>

To verify file copied correctly, maybe just put above in a Try... Catch...
Or should I check CRC or something to see if copied correctly?

3) If anyone has done something similar, are there any pitfalls or things I should watch out for?

Tks.

Re: File Synchronization/Backup

Dave Kreskowiak9-Nov-09 5:18

Dave Kreskowiak

9-Nov-09 5:18

2). You can use File.Copy the copy the files over, wrapped in a Try/Catch block. You don't have to check the file contents yourself since the O/S takes care of that for you. Since File.Copy is a blocking call, any errors encountered will throw an exception you can catch.

3) Yeah, but I didn't write my own system to do this. I used the MS Sync Framework[^].

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

CD-RW help

offroaderdan9-Nov-09 4:34

offroaderdan

9-Nov-09 4:34

Hi,
I have been searching google for the answer but can't seem to get anywhere.

I have a small program that asks the user for a registration key, they type in the key lets say its "password" the term "password" is then checked on a .txt file in the debug folder and if it is correct they can then install the program on to the hardrive.

This worked brillinat on vb.net however it doesn't work on cd-rw disc.

I WOULD LIKE TO KEEP SOME SECURITY ON THIS PROGRAM that is why i am planing on using CD-RW

i was oringally having the .txt file so that the contents of that .txt file was deleted. is there anyway that the whole file could be dleted or would that still upset the cd-rw???

there must be away round this!?

Dan