Coerce Windows to show a thumbnail for my custom file type.

Question

Hi, I want to use the windows OpenFileDialog class in C# to browse files for my application. I would then like the files to show up with previews in Windows' "thumbnails" view.

Is there a simple way to make this happen? I'm thinking there should be a way to encode the files so that Windows simply reads and displays the thumbnail information, even though it's an unsupported file type?

I know Windows Vista has a different interface (IThumbnailProvider as opposed to IExtractImage) than Windows XP, but I need it to work across platforms.

Thanks! / Jakob

Answer 1

You have to write a Shell Extension Handler Thumbnail Image Extractor. This is unmanaged c++ code that extracts the image from your custom filetype to display within explorer shell. You can find more about Shell Extension Handlers at the following link:

Creating Shell Extension Handlers