Use the ON_EVENT macro to define an event handler function for an event fired by an OLE control.
The class to which this event sink map belongs.
The control ID of the OLE control.
The dispatch ID of the event fired by the control.
Pointer to a member function that handles the event. This function should have a BOOL return type, and parameter types that match the event's parameters (see vtsParams). The function should return TRUE to indicate the event was handled; otherwise FALSE.
A sequence of VTS_ constants that specifies the types of the parameters for the event. These are the same constants that are used in dispatch map entries such as DISP_FUNCTION.
The vtsParams argument is a space-separated list of values from the VTS_ constants. One or more of these values separated by spaces (not commas) specifies the function's parameter list. For example:
specifies a list containing a short integer followed by a BOOL.
For a list of the VTS_ constants, see EVENT_CUSTOM.