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How to: Access Events in Interfaces

The accessibility of a raise method is never public and is protected by default. A raise method is private if the event is private, and virtual if the event is declared virtual. If an event is declared in a managed interface, only its add and remove methods can be implemented.


// mcppv2_events2.cpp
// compile with: /clr
using namespace System;

delegate void Del(int, float);

// interface with event and a function to invoke event
interface struct I {
   event Del ^ E;
   void fire(int, float);   

// class that implements interface event and function
ref class EventSource: public I {
   virtual event Del^ E;
   virtual void fire(int i, float f) {
      E(i, f);

// class that defines event handler
ref class EventReceiver {
   void Handler(int i , float f) {

int main () {
   I^ es = gcnew EventSource();
   EventReceiver^ er = gcnew EventReceiver();

   // hook handler to event
   es->E += gcnew Del(er, &EventReceiver::Handler);

   // call event
   es -> fire(1, 3.14);

   // unhook handler from event
   es->E -= gcnew Del(er, &EventReceiver::Handler);



See Also