Open a JPG in an encrypted zip file

[szlamany]

We want to put JPG images of students on a pocket PC.

We were thinking of putting them into an encrypted zip file to protect the images from loss.

Is it possible to use New Bitmap("zip folder\xyz.jpg" in some way?

Any other ideas on how to accomplish this?

[Atheist]

The System.IO.Compression.GZipStream class will let you put stuff in zip files. Not sure if it works on pocket pcs though..

[szlamany]

Of course it's not there - this VS for PPC is so stripped down...

Arrgghh...

[Hack]

Moved at member's request

[szlamany]

Hate to bump this - but I'm still looking for some suggestions...

Any ideas on how a folder can be encrypted on a PPC so that the JPG images in it cannot be viewed outside my app?

There might be so many images that an SD card will be used to hold them.

[petevick]

Hi,
you can use the sharplib free zip class, and zip and unzip them, and give them a different extension, so double-clicking wouldn't automatically unzip them. Then unzip to a temp file, and load up the temp file.

Otherwise there are several 3rd party libraries for zipping, including Resco and n/software

Pete

[szlamany]

Does the zip's you suggest support encryption?

The idea is that when a user clicks on a student name they get the student schedule and also see the picture of the student on top of that schedule (it disappears if they click the picture).

This is working fine right now - each student image is a separate JPG - and I show them like this:

        Dim l_bmp As Bitmap
        Try
            l_bmp = New Bitmap(strBaseFolder & "\" & "000000".Substring(0, 6 - strId.Length) & strId & ".jpg")
            pbxStudent.Image = l_bmp
            pbxStudent.Visible = True
            pbxStudent.BringToFront()
        Catch ex As Exception
            pbxStudent.Visible = False
        End Try

So - it sound like the method you suggest might be slow in comparison to what I'm doing now. I could copy out the picture from the zip file - but then I have to be careful to delete and so on.

[petevick]

Hi,
that is similar to what we do now to view signatures held as pictures.

Not tried it, but I would guess if you changed the extension of the file from .jpg to .xxx then you should still be able to load them as you do, but double-clicking on them by a user in explorer would do nothing

Pete

[szlamany]

...
Not tried it, but I would guess if you changed the extension of the file from .jpg to .xxx then you should still be able to load them as you do, but double-clicking on them by a user in explorer would do nothing

Pete

I agree - I already changed the .SDF extension to .DLH (don't look here!)...

But having 1200 jpgs with .XYZ extensions in a folder - and the PPC gets lost - it might not take too much time for someone to figure out that they might be pictures. I'm concerned about having 1200 student images get lost and hit the newspapers! Especially with my app being responsible!

I wonder if SQL CE can store IMAGE or BINARY data - I might look into that next...

[Strider]

yes sqlce can store images... i use it storing signature capture on the devices before sending them over WebService to our SQL Server... dont know how fast it will be, depending on the size of your images.

[szlamany]

yes sqlce can store images... i use it storing signature capture on the devices before sending them over WebService to our SQL Server... dont know how fast it will be, depending on the size of your images.

Thanks!

Would you mind posting some examples of loading an image into a SQL CE field and retrieving it?

Thanks again!

[Strider]

i will tomorrow... but i can tell you i save the signature as a bitmap, then read in the bitmap and store in sqlce before deleting the image.

i haven't tried reading an image from SqlCe using CF, only on the full framework and there are lots of examples, but im sure it can be done.

i nice idea would be to populate a sql server database with the the data including the images, and use RemoteDataAccess(RDA) or Replication to pull it onto the device (this is very fast).