ArcGIS Engine Developer Guide

BUILDING APPLICATIONS WITH C++ AND CONTROL WIDGETS
// Load the same pre-authored map document into the MapControl
CComBSTR DocFileName;
IPageLayoutControl2Ptr ipPage2 = g_ipPageLayoutControl;
ipPage2->get_DocumentFilename(&DocFileName);
g_ipMapControl->LoadMxFile(DocFileName);
}
6. Since events have been added, you need to tell the main application to listen
for them. Do this by creating an instance of the new class in the main function
of MapViewer.cpp and by using the IEventListenerHelper interface.
a. First, include PageLayoutControlEvents.h at the top of MapViewer.h.
#include
// Events
#include "PageLayoutControlEvents.h"
b. In MapViewer.cpp, declare the global variables to use in listening for events.
IPageLayoutControlPtr g_ipPageLayoutControl;
// Events
PageLayoutControlEvents* g_pageLayoutEvents;
IEventListenerHelperPtr g_ipPageLayoutControlEventHelper;
c. Place the code to begin listening after the FormSetup in main, and before the
data is loaded.
FormSetup(argc, argv, &app_context);
In GTK, the event cleanup will be done in
delete_event, a callback used with
destroy_event to close the application.
// Event listening
g_pageLayoutEvents = new PageLayoutControlEvents();
g_ipPageLayoutControlEventHelper.CreateInstance(
CLSID_PageLayoutControlEventsListener);
g_ipPageLayoutControlEventHelper->Startup(
static_cast(g_pageLayoutEvents));
g_ipPageLayoutControlEventHelper->AdviseEvents(g_ipPageLayoutControl,
NULL);
7. Before closing the application, you must clean up the events by calling
UnadviseEvents and Shutdown, as well as deleting the instance of
PageLayoutControlEvents. This is done in CloseAppCallback before the control
interface pointers are set to 0.
// Function called when WM_DELETE_WINDOW protocol is passed
void CloseAppCallback(Widget w, XtPointer client_data, XtPointer call_data)
{
// End event listening
g_ipPageLayoutControlEventHelper->UnadviseEvents();
g_ipPageLayoutControlEventHelper->Shutdown();
g_ipPageLayoutControlEventHelper = 0;
delete g_pageLayoutEvents;
g_ipToolbarControl = 0;
Chapter 6 • Developer scenarios • 373