Windows Search - IFilter search term highlighting

You need to generate a Preview Handler for your file type.

It can also render enhanced previews of items in a Preview Pane without launching the default application, if the application has registered a Preview Handler. This can provide functionality such as file type-specific navigation (such a browsing a presentation using next/previous controls, or seeking inside a media file).[29] Preview handlers can also allow certain kind of selections (such as highlighting a text snippet) to be performed from the preview pane itself.

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There's a bunch of code examples floating around for PDFs and such.

Take a peek here: CodePlex:Windows Preview Handler Pack

Edit:

To clarify, the search results pane in Windows 7 is a preview handler host. It has two main pieces: the Content View and the Preview Pane.

Windows Explorer also includes a view mode called the Content view, which is the default view when viewing search results. The Content view shows the name, location, some of the metadata tags associated with the file, a thumbnail image of the file, and a snippet of the file. This view mode also uses hit highlighting to show where the query term appears in the files, which makes it easy to understand why that file was returned in the search results list.

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You need a Preview Handler for any custom file types if you want enhanced functionality like viewing the file contents for your custom file type.

In Windows Vista and later, Windows Search is integrated into all Windows Explorer windows for instant access to search.

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Preview handlers and thumbnail handlers enable users to preview documents in Windows Explorer without having to open the application that created them.

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To verify that you have implemented your custom file type correctly, you can try the File Type Verifier from the Windows 7 SDK, which will test the following things assosicated with your custom file:

• Preview Handlers
• Thumbnail Handlers
• Property Handlers
• Verb Handlers
• Filters (IFilter)
• Kind Associations
• Perceived Types
• Important Properties

Using the Content View

you can take advantage of the Content view by using either of two different approaches. You can use an existing set of properties and layout pattern, or you can create your own combination. These two approaches are described in detail:

• Associating Your File Type or Item with an Item Kind
• Registering a Unique Content View Set of Properties and Layout Pattern for the File Type or Item

For a general overview on the Content View, see this article:

Content View By File Type or Kind