Providing online Help for users
Two ways to call Help from an application
PowerBuilder provides two principal ways of calling an online
Help file from a PowerBuilder application:
- Use the ShowHelp and ShowPopupHelp PowerScript
functions in your application scripts to call Help topics. - Declare the WinHelp API as an external function
and use the WinHelp function in your application
scripts to call Help topics.
Using ShowHelp
ShowHelp is simpler to implement than the
WinHelp API. You can use the ShowHelp PowerScript
function to search for Help topics by Help context ID, by keyword,
and by accessing the Help file Contents topic (the topic defined
in the project file as the Help Contents topic). ShowHelp can
also be used with compiled HTML (.chm) files.
ShowPopupHelp displays pop-up help for
a control. Typically, you use ShowPopupHelp in
the Help event of a response window with the Context Help property
enabled. Events relating to movement of the cursor over a control
or to the dragging of a control or object are also logical places
for a ShowPopupHelp call.
For more information on the ShowHelp and ShowPopupHelp functions
as well as the Help event, see the PowerScript Reference
.
Using the WinHelp API
Declaring and using the WinHelp API allows access to the full
range of WinHelp functions, many of which are not available in ShowHelp.
For example, using the WinHelp function, you
can easily specify a window type or window name in which to present
a Help topic.
To declare the WinHelp API as an external function:
-
Select Declare>Global External
Functions from the menu bar of any painter that accesses the Script
view. -
Enter the function declaration in the text box
and click OK.This example declares the WinHelp API:
1FUNCTION boolean WinHelpA(long hWndMain, &1string lpszHelp, long uCommand, &1long dwData) &1LIBRARY "USER32.DLL"
For more information about the WinHelp API,
see the online Help for the Microsoft Help Workshop or the documentation
for your Help authoring tool. For more information about declaring
and using global external functions, see the PowerScript
Reference
and “Using external functions”.
This part presents a collection of techniques you can
use to implement data access features in the applications you develop
with PowerBuilder. It includes using Transaction objects, XML processing,
graphs, rich text, and piping of data between data sources. The
use of DataWindow objects and DataStores for data access is described
in the DataWindow Programmer’s Guide
.