Release 10.1A: OpenEdge Development:
Programming Interfaces

> ## Accessing online help from the menu bar

> A common method of requesting help from an application is by selecting help items from the application menu bar. The menu bar usually includes a help pull-down menu and contains menu items such as:

> - Help Topics — Instructs the help engine to display the HTML Help Viewer for the specified help file.

> - About or Version — Provides application copyright and version number information.

> The `CHOOSE` event occurs when a user chooses an option from a menu. In the Progress 4GL, you use a `CHOOSE` event to code a trigger for menu items.

> The following code example demonstrates a help trigger that executes when the user selects a menu item from the application’s menu bar to access the help engine:

>     ON CHOOSE OF MENU-ITEM menu_help_contents
>     		DO:
>     			SYSTEM-HELP myhelp.chm CONTENTS.
>     		END.

> ##### Calling the Help Viewer

> Using the `CONTENTS` option of the `SYSTEM-HELP` statement displays the HTML Help Viewer for the specified help file. You frequently use this for a Help Topics call from the help menu. The following code example demonstrates a Help Topics call:

>     ON CHOOSE OF MENU-ITEM Help_Topics:
>     		DO:
>     			SYSTEM-HELP myhelp.chm CONTENTS.
>     		END.

> For example, when the user chooses the Help Topics from the Help menu in the Procedure Editor’s main window, the Help Viewer appears, as shown in Figure 10–4.

> Figure 10–4: HTML Help Viewer showing Procedure Editor help

> ##### Calling the Index function of the Help Viewer

> Like the Help Topics call, it is common to call the Index function of the Help Viewer from the Help menu. The following pseudocode calls the Help Viewer with the Index tab on top:

>     ON CHOOSE OF Button_Search IN FRAME frame_1
>     		DO:
>     			SYSTEM-HELP myhelp.chm KEY "".
>     		END.

> Figure 10–5 shows the Help Viewer for the Procedure Editor help file with the Index tab on top.

> Figure 10–5: Help Viewer with Index tab on top

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