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ISpecialWinHelpViewer = interface(IExtendedHelpViewer)


__interface  INTERFACE_UUID("{1A7B2224-1EAE-4313-BAD6-3C32F8F77085}") ISpecialWinHelpViewer  : public IExtendedHelpViewer


Type Visibility Source Unit Parent
System.HelpIntfs System.HelpIntfs


Help Viewer that supports special Windows Help requests.

ISpecialWinHelpViewer supports Help requests that cannot be easily generalized and should only be handled by the Microsoft Windows Help engine or a closely compatible application.

ISpecialWinHelpViewer declares the single method System.HelpIntfs.ISpecialWinHelpViewer.CallWinHelp, which should pass the Help request to the Help engine with as little manipulation as possible. An application needs to provide only one Viewer that implements ISpecialWinHelpViewer. If more than one Viewer that implement ISpecialWinHelpViewer are registered, then only the first Viewer receives calls to CallWinHelp.

The Vcl.HtmlHelpViewer (and obsolete Vcl.WinHelpViewer) unit provides the implementation for the CallWinHelp method. CallWinHelp is called by the Help Manager when it receives an HTMLHelp-style or WinHelp-style help request from the third-party designed help system and is not able to deconstruct it into something meaningful for the third-party help viewer. That is, CallWinHelp is intended to allow third-party help systems to process messages that are not generalizable by the third-party help system designer. These help requests are forwarded to proper HTMLHelp (or WinHelp) native functions in all circumstances.

See Also