Delphi What Is The DelphiVCL.Application.HelpCommand?

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What Is The DelphiVCL.Application.HelpCommand?
By Muhammad Azizul Hakim October 5, 2021

We can use the HelpCommand method or DelphiVCL.Application.HelpCommand to provide access to any of the Help commands in the application programming interface (API) of native Help handling functions HTMLHelp, WinHelp, or others.

Use HelpCommand to send a command to HTMLHelp, WinHelp, or other native Help handling functions. Before sending the Help command to the native (Windows) help engine, HelpCommand generates an OnHelp event on the active form or the TApplication object. Finally, the command is forwarded to the native Help handling functions (HTMLHelp or WinHelp) if there is no event handler for the OnHelp event.

In order for HelpCommand to work and to call the proper native Help handling function, insert in the uses clause of your application the Vcl.HtmlHelpViewer unit or another unit that provides an interface to the external Help viewer to use. The Vcl.HtmlHelpViewer unit provides a Delphi interface to the HTMLHelp Windows native Help handling function. For C++, you need to include the HTMLHelpViewer.hpp header files.

For information about the native Help handling functions (HTMLHelp or other) and about the data passed to them, see the appropriate HTMLHelp topics in the MSDN Library.

How to browse the properties, and methods of DelphiVCL.Application.HelpCommand?​

Let’s browse all the properties and methodsof the DelphiVCL.Application.HelpCommand using dir() command:
Python:
import DelphiVCL
 
dir(DelphiVCL.Application.HelpCommand)
See the responses in our Windows command prompt:
1633504251335.png
You can also read short information about the DelphiVCL.Application.HelpCommand using the print() command:
Python:
print(DelphiVCL.Application.HelpCommand)
print(DelphiVCL.Application.HelpCommand.__doc__)
See the responses in our Windows command prompt:
1633504289729.png