Extend the Common Dialog Boxes Using Windows Forms 1.x

Smart Client Developer Center: Extend the Common Dialog Boxes Using Windows Forms 1.x

"Describes some techniques for placing Windows Forms controls inside the standard File Open dialog box. You can use this ability to provide 'preview' or 'open as' behavior in your own applications. The same techniques can be applied to the other common dialog boxes. (8 printed pages)

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Sounds interesting.