ArcGIS Engine Developer Guide

BUILDING APPLICATIONS WITH C++ AND CONTROL WIDGETS
ipActiveView->get_FocusMap(&ipFocusMap);
IActiveViewPtr ipMapActiveView(ipFocusMap);
ipMapActiveView->get_Extent(&g_ipCurrentExtent);
// Load the same pre-authored map document into the MapControl
…
}
6. The PageLayoutControlEvents do not indicate when the extent of the map
within the data frame changes. To receive that information you will use the
ITransformEvents interface of the PageLayoutControl’s focus map. Implementing
a class, TransformEvents, that extends ITransformEvents accomplishes this. It
will need to update the extent envelope and refresh the MapControl in
VisibleExtentUpdated. To do so, your new class will need access to the
g_ipMapControl and g_ipCurrentExtent global variables. Create a new file,
TransformEvents.h, with the following code:
#ifndef __TRANSFORMEVENTS_H_
#define __TRANSFORMEVENTS_H_
// ArcObjects Headers
// Engine
#include
// Controls
#include
extern IMapControl3Ptr g_ipMapControl;
extern IEnvelopePtr g_ipCurrentExtent;
class TransformEvents : public ITransformEvents
{
public:
// IUnknown
IUNKNOWN_METHOD_DEFS
// ITransformEvents
HRESULT BoundsUpdated(IDisplayTransformation* sender);
HRESULT DeviceFrameUpdated(IDisplayTransformation* sender,
VARIANT_BOOL sizeChanged);
HRESULT ResolutionUpdated(IDisplayTransformation* sender);
HRESULT RotationUpdated(IDisplayTransformation* sender);
HRESULT UnitsUpdated(IDisplayTransformation* sender);
HRESULT VisibleBoundsUpdated(IDisplayTransformation* sender,
VARIANT_BOOL sizeChanged);
};
#endif // __TRANSFORMEVENTS_H_
7. Implement that class by placing the following code in TransformEvents.cpp,
another new file. In particular, pay attention to VisibleBoundsUpdated. This
event is triggered whenever the extent of the map is changed and is used to
Chapter 6 • Developer scenarios • 385