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_DeActivateHandler( ) API Library Routine

  • Articolo

_DeActivateHandler( ) removes the specified event handler from the event processor list.

void _DeActivateHandler(unsigned int EventIdentifier)
unsigned int EventIdentifier;      /* ID of event handler
 to be removed from list. */

Remarks

You must remove each event handler, indicated by EventIdentifier, from the handler list when its library is unloaded.

For more information on how to create an API library and integrate it with Visual FoxPro, see Accessing the Visual FoxPro API.

Example

The following example activates an event handler when the library is loaded. The event handler prints a message for every event and lets Visual FoxPro process the message. The event handler is deactivated when the library is unloaded. As in the following example, _DeActivateHandler( ) is usually called from a CALLONUNLOAD function.

Visual FoxPro Code

SET LIBRARY TO DEACTHAN

C Code

#include <pro_ext.h>

static int HandlerID;

//   This is the routine that is registered as an event handler.
FAR EventHandler(WHandle theWindow, EventRec FAR *ev)
{
   _PutStr("\nEventHandler() called.");
   return NO;   // event still needs to be handled by Visual FoxPro
}

FAR Activate()
{
   HandlerID = _ActivateHandler(EventHandler);
}

//   When the library is unloaded we must deactivate the event handler
//   in a CALLONUNLOAD function.
FAR DeActivate()
{
   _DeActivateHandler(HandlerID);
}

FoxInfo myFoxInfo[] = {
   {"ACTIVATE",  (FPFI) Activate, CALLONLOAD, ""},
   {"DEACTIVATE", (FPFI)  DeActivate, CALLONUNLOAD, ""}
};
FoxTable _FoxTable = {
   (FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};

See Also

_ActivateHandler( ) API Library Routine | _FindWindow( ) API Library Routine | _GlobalToLocal( ) API Library Routine | _MousePos( ) API Library Routine