ArcGIS Engine Developer Guide

VISUAL C++
This environment does not support controls finding other controls at design
time. However, this step can be performed in code using the OnInitDialog
method.
// Note no addref performed with GetControlUnknown, so no need to release
this pointer.
LPUNKNOWN pUnk = m_mapcontrol.GetControlUnknown();
LPDISPATCH pDisp =
0;pUnk->QueryInterface(IID_IDispatch, (void **) &pDisp);
// Set TOCControls buddy to be MapControl.
m_toccontrol.SetRefBuddy(pDisp);
pDisp->Release();
8. Right-click the control and choose Class Wizard to launch the class wizard.
Click the Member Variables tab and click the resource ID corresponding to the
control to give the control a member variable name. The dialog box class
member variable can now be used to invoke methods and properties on the
control.
Visual Studio C++ Class Wizard. Adding member
variables to the dialog box for the ActiveX
controls.
Do not use the method GetIDispatch (inherited
from MFC’s CCmdTarget) on the wrapper
classes; it is intended for objects implementing
IDispatch and not the wrapper classes that are
calling IDispatch. Instead, to get a control’s
IDispatch, use
m_mapcontrol.GetControlUnknown()
followed by QueryInterface to IDispatch. See
the above example of setting the Buddy
property.
9. To catch control events, click the Message Maps tab of the class wizard and
choose the resource ID of the control. In the list of messages, click the event
to catch—for example, OnBeginLabelEdit. Double-click this event and a
handler for it will be added to your dialog box class. By default, the wizard
will add an extra word, “On”, to the beginning of the event handler. Remove
this to avoid the event handler name becoming OnOnBeginLabelEditToccontrol1.
HANDLING COM EVENTS IN ATL
Below is a summary of terminology used here when discussing COM events in
Visual C++ and ATL.
Inbound interface—This is the normal case where a COM object implements a
predefined interface.
128 • ArcGIS Engine Developer Guide