From the Windows standpoint, the slide show application is a very simple SDI (Single Document Interface) application. CchildView::OnPaint() displays a GDI Image object that represents the current image. The other events and commands are all handled in the CMainFrame class, which implements the top level main frame window of the application.
The ImageSource class handles retrieving pictures from one of several components and presenting the images in sequence.
When a memory stick, flash card, or USB hard drive is inserted or removed, the Windows system automatically sends WM_DEVICECHANGE messages to the top level window of each application. CMainFrame::OnDeviceChange() sorts out the messages that signal media insertion and removal. The Slide Show application responds to the insertion by attempting to display picture files in the root folder.
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