Fire an event in native C++ dll and catch in C++/CLI

Question

0.00/5 (No votes)

See more:

Hello guys!
Is there a way to handle a native C++ event in C++/CLI? How should I make the hook?
I searched almost all day on the internet but haven't found the answer. I hope you have any idea.

C++

class Native{
public:
	__event void myEvent(int i);
	void fireEvent(){
		__raise myEvent(1598);
	};
};

public ref class Managed{
	Native* nativeObject;
public:
	void fireEventHandler(int i){
                printf("Event handled!\n");
        };

	Managed(){
		nativeObject=new Native();
		__hook(&Native::myEvent, nativeObject, &Managed::fireEventHandler );
	};
};

If I try to compile this, I get an error:

error C3731: incompatible event 'void Native::myEvent(int)' and handler 'void Managed::fireEventHandler(int)'; event source and event handler must have the same event type.
1>          The event type of 'Native' is 'native'.
1>          The event type of 'Managed' is 'managed'.

In my application, the native class is compiled in separate DLL without a \clr option, so I cannot hold a reference to managed object.

Thank you in forward!

Posted 7-Mar-12 5:01am

peto2242

Add a Solution

2 solutions

Solution 1

Hope this will help

http://msdn.microsoft.com/en-us/library/367eeye0(v=VS.100).aspx[^]

Posted 7-Mar-12 20:05pm

Lakamraju Raghuram

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

peto2242 · Accepted Answer · 2012-03-07T21:33:00

Thank you Lakamraju, actually I've found the solution myself yesterday evening, but this article helped me also, because I didn't think about garbage collector relocation.
My solution is here:

C++

// EventTesting.cpp : main project file.

#include "stdafx.h"
#include "stdio.h"

using namespace System;
using namespace System::Runtime::InteropServices;

class Native{
public:
	void (*myEvent)(int i); // function pointer declaration 
	Native(){
		myEvent=NULL;
	}
	void fireEvent(int i){
		if(myEvent!=NULL) myEvent(i);// calling function thru pointer
	};
	void setmyEventHandler(void (*func)(int i)){
		myEvent = func;// Initializing the function pointer with the incoming one
	}

};

private delegate void myEventDelegate(int i);

public ref class Managed{
	Native* nativeObject;
	myEventDelegate ^ del;
	GCHandle delH;
public:
	void fireEventHandler(int i){
		printf("EVENT FIRED %d\n",i);
	};

	Managed(){
		nativeObject=new Native();
		del = gcnew myEventDelegate(this, &Managed::fireEventHandler);
		delH = GCHandle::Alloc(del);
		System::IntPtr d1 = System::Runtime::InteropServices::Marshal::GetFunctionPointerForDelegate(del);
		nativeObject->setmyEventHandler(( void(*)(int))d1.ToPointer());// Calling unmanged library function to initialize function pointer 
	};
	~Managed(){	//Cleanup
		nativeObject->setmyEventHandler(NULL);
		delete nativeObject;
		delH.Free();
	}
	void testEvent(){
		nativeObject->fireEvent(1598);
	}
};


int main(array<system::string xmlns:system="#unknown"> ^args)
{
    Managed^ managedClass = gcnew Managed;
    GC::Collect();
    managedClass->testEvent();
    return 0;
}</system::string>

The only problem with this solution is that we can "register" only one "event handler"... actually this is not an event, just a callback.
Thank you once again!