File dialog user interfaces and creation of same

摘要

An OS generates a file dialog in response to a request from an application program. The file dialog has a format with a dedicated extensibility region. Multiple user interface controls from a predefined collection of UI control types can be placed within the extensibility region. An application requesting display of a file dialog requests one or more controls of the types in the predefined collection. The OS then places the requested controls in the extensibility region of the displayed dialog. The application need not provide data explicitly indicating the positions within the dialog of the requested controls.