Custom preview for open dialog using Delphi

I need to preview several CAD formats in the file open dialog box in Windows 7 / Vista. In the past I used a Delphi Preview Open Dialog and I could register and implement the CAD format that I had to preview. I have found some articles on how to create a preview handler in Vista, this is unfortunately no开发者_C百科t going to work for me. What I would like to know if there is a way that I can get hold of the IPreviewHandler interface of the dialog that I have created

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I've searched about these before, but I couldn't find exact solution.

I found that Microsoft offers the IFileDialogCustomize interface to modify new file dialogs for vista or later. According to this article, we can't add any custom controls like as XP or before, and the controls we can add are very limited as below.

The provided controls are:

* Menu
* Button
* Combo box
* Radio button list
* Check button (check box)
* Edit
* Separator
* Label

If there's no other interfaces provided from MS, we can't properly extend the file dialog.

I think the things we can provide at this time is:

• open custom window on the side of the file dialog.

  Have you ever used IrfanView ? If you save image as png or jpeg format, IrfanView shows option setting window on the right side of the save dialog(below one is customized in traditional way, but perhaps we can do similar with new dialog). alt text http://img208.imageshack.us/img208/9128/irfanviewsaveas.png

• mimic new dialog using shell controls & some new custom controls

  It's probably not so good because perhaps we can't find enhanced tree control on the left side, but with rkSmartPath we can mimic new path bar as below. (I think it's great work!)

If someone implement mimic control of Windows 7's new place bar/tree using virtual tree view or something, we could provide good customized dialog. (even for XP users.)

# I think it's chance for component vendors to develop solution for this problem...

# It's a gift from Microsoft for you! :-)