A simpler way to trigger events in a visual extension uses direct mapping of Windows messages to PowerBuilder events. The following class description contains the same two events, but in this case they use the alternative syntax that maps the event name to a PowerBuilder token name:
PBXEXPORT LPCTSTR PBXCALL PBX_GetDescription()
{
static const TCHAR desc[] = {
"class visualext from userobject\n"
"event onclick pbm_lbuttonup\n"
"event ondoubleclick pbm_lbuttondblclk\n"
"subroutine setcolor(int r, int g, int b)\n"
"subroutine settext(string txt)\n"
"end class\n"
};
return desc;
}
Importing the extension generates the Onclick and Ondoubleclick events with the appropriate arguments automatically, and at runtime, the PBVM fires the events. You do not need to capture the Windows messages WM_LBUTTONUP and WM_LBUTTONDBLCLK in the extension.
In the following description, onclick is the event name and pbm_lbuttonup is the event token name. Notice that the event name is not followed by empty parentheses as it is when you use the return type and arguments technique for describing the event:
"event onclick pbm_lbuttonup\n"
The token name is a string that maps to an internal PowerBuilder event ID defined in the header file pbevtid.h. The first ID in this file is PB_NULL. For all other IDs in the file, there is a fixed relationship between the name that you use in the description and the event ID in pbevtid.h. The name is the same as the ID with the letter m appended to the pb prefix. You must use lowercase in the description.
For example, the event ID PB_ACTIVATE in pbevtid.h maps to the token name pbm_activate. In the description provided with PBX_GetDescription, you must use the name pbm_activate. If the event name you provide does not exist, importing the extension generates an error message. See the pbevtid.h file for a complete list of mapped IDs.
