ArcGIS Engine Developer Guide

VISUAL C++
BEGIN_CONNECTION_POINT_MAP(CMyEventSource)
CONNECTION_POINT_ENTRY(DIID_ITOCControlEvents)
END_CONNECTION_POINT_MAP()
};
The connection point class (TOCControlEventsCP.h in the above example) contains
code to fire an event to all sink objects on a connection point.
There is one method in the class for each event beginning “Fire_”. Each method
will build a parameter list of variants to pass as an argument to the dispatch
Invoke method. Each sink is iterated, and a pointer to the sink is stored in a
vector m_vec member variable inherited from IConnectionPointContainerImpl. Note
that m_vec can contain pointers to 0; this must be checked before firing the
event.
template
class CProxyITOCControlEvents : public IConnectionPointImpl
{
public:
VOID Fire_OnMouseDown(LONG button, LONG shift, LONG x, LONG y)
{
// Package each of the parameters into an IDispatch argument list.
T* pT = static_cast(this);
int nConnectionIndex;
CComVariant* pvars = new CComVariant[4];
int nConnections = m_vec.GetSize();
// Iterate each sink object.
for (nConnectionIndex = 0; nConnectionIndex < nConnections;
nConnectionIndex++)
{
pT->Lock();
CComPtr sp = m_vec.GetAt(nConnectionIndex);
pT->Unlock();
IDispatch* pDispatch = reinterpret_cast(sp.p);
// Note m_vec can contain 0 entries, so it is important to check for
this.
if (pDispatch != NULL)
{
// Build up the argument list.
pvars[3] = button;
pvars[2] = shift;
pvars[1] = x;
pvars[0] = y;
DISPPARAMS disp = { pvars, NULL, 4, 0 };
// Fire the dispatch method. 0x1 is the DispatchId for MouseDown.
pDispatch->Invoke(0x1, IID_NULL, LOCALE_USER_DEFAULT,
DISPATCH_METHOD, &disp, NULL, NULL, NULL);
}
}
Chapter 4 • Developer environments • 137