System.HelpIntfs.IExtendedHelpViewer.UnderstandsTopic
Delphi
function UnderstandsTopic(const Topic: string): Boolean;
C++
virtual bool __fastcall UnderstandsTopic(const System::UnicodeString Topic) = 0 ;
Properties
| Type | Visibility | Source | Unit | Parent |
|---|---|---|---|---|
| function | public | System.HelpIntfs.pas System.HelpIntfs.hpp |
System.HelpIntfs | IExtendedHelpViewer |
Description
Queries the Help Viewer whether it understands the given Topic string.
UnderstandsTopic should return True if the Help Viewer can identify any topic having the topic name provided in the Topic parameter.
Topic must be unique for all the topics maintained by a particular Help Viewer. In case of a .chm help file, Topic should be the name of the source .htm file that contains the topic.
When the Help System receives a Topic-based Help request, it calls UnderstandsTopic for each Help Viewer that it has registered until the method returns True. Help Viewers are polled in the order they were registered with System.HelpIntfs.RegisterViewer. The Help System then calls that Help Viewer's DisplayTopic method.
In order to use UnderstandsTopic, insert in the uses clause of your application the Vcl.HtmlHelpViewer or another unit that provides an interface to the external Help viewer to use. For C++, you need to include the HTMLHelpViewer.hpp header file.