_DeActivateHandler( ) API Library Routine

Visual FoxPro 9.0 SP2

_DeActivateHandler( ) API Library Routine


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

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SET LIBRARY TO DEACTHAN

C Code

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#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 };

Copy 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
};

_DeActivateHandler( ) API Library Routine

Remarks

Example

Visual FoxPro Code

C Code

See Also

Reference

Concepts

Other Resources