On 2/15/07, Eric Richards <[EMAIL PROTECTED]> wrote:
>
> Think of your VirtualVolume file as a file system, and root is the
> highest directory you can access.
>
> I have an application whose file format is a bunch of different
> folders within the root, each of which may contain anywhere from one
> to several different files. I chose to organize it that way to keep it
> better organized from my perspective. The files could have all been
> stored within the root (i.e. no subfolders), instead, but I chose this
> way of doing it. It's totally up to you.
>
> So the way you get something out of a VirtualVolume file is to get the
> root FolderItem and then dig down from there to wherever you have
> saved your data in the structure you created. Hope that makes sense.
>
Ahh.. ok.
Well I got a VV file made and stuffed with data.. I think.
Now getting it out seems a bit tricky. I want
to get each file (Name) listed in a listbox.
Dim vv As VirtualVolume
Dim realFile As FolderItem
Dim virtFile As FolderItem
Dim inp As BinaryStream
realFile = GetFolderItem("").Child("VirVol")
vv = realFile.OpenAsVirtualVolume
If vv = Nil then
MsgBox "Unable to open virtual volume"
else
virtFile = vv.Root.child("Data")
inp = virtFile.openAsBinaryFile()
//ListBox1.addRow inp.readPString
end if
exception
quit
Careful with how much data you plan to store in VVs. I tried with my
large (100 MB) image files and VV's were 10-100 times slower (and th.f
unusable for me) than a single flat file. For small data sets it
should work fine.
I have a quick project that runs a comparison if you wan to tryt.
P.
-------------------------------------------------------------------------------
Peter K. Stys, MD
Professor of Medicine(Neurology), Senior Scientist
Ottawa Health Research Institute, Div. of Neuroscience
Ottawa Hospital / University of Ottawa
Ontario, CANADA
tel: (613)761-5444
fax: (613)761-5330
http://www.ohri.ca/profiles/stys.asp
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