C ++ native code DLL using abstract class wrapped to be used in C # module
Hi I have the same problem with an abstract class. I am trying to wrap my cpp DLL calls for use in a C # module.
Dll uses Factory pattern which contains Factory class, MiddileWare and corresponding strong child class . Can anyone help me start the shell. I'm stuck in between. Your help will be appreciated. I give a stream here:
MiddleWareFactory.h
#pragma once
#include "MiddleWareConnection.h"
#include "std afx.h"
#ifdef MIDDLEWAREFACTORY_EXPORTS
#define MIDDLEWAREFACTORY_API __declspec(dllexport)
#else
#define MIDDLEWAREFACTORY_API __declspec (dllimport) #endif
MIDDLEWAREFACTORY_API enum eMiddleWareEngine
{
eRabitMQ = 0,
eZeroMQ,
eActiveMQ
};
// This class is exported from the MiddleWareFactory.dll
class MIDDLEWAREFACTORY_API CMiddleWareFactory
{
public:
CMiddleWareFactory(void);
~CMiddleWareFactory();
// TODO: add your methods here.
//Function to Create the object of Broker module:implemnted the Factory concept.
BOOL CreateInstance(CMiddleWareConnection** pMObj);
int m_eMomEngine;//To define which MOM need to enable.
};
extern MIDDLEWAREFACTORY_API int nMiddleWareFactory;
MIDDLEWAREFACTORY_API int fnMiddleWareFactory(void);
MiddleWareConnection.h
#pragma once
class CMiddleWareConnection {public:
virtual ~CMiddleWareConnection(void)
{
}
//Pure virtual fuctions for interfacing
virtual BOOL Connect(int nServerType)=0;
virtual BOOL CreateSessionExchange() = 0;
virtual BOOL CreateQueue(LPCTSTR lpszQueueName) = 0;
virtual BOOL Disconnect() = 0;
virtual BOOL Send(void *MomItem,LPCTSTR lpszKey, int &nSendCount)=0;
virtual BOOL Receive() = 0;
virtual void StopReceiver() = 0;
virtual void GetData(void* pMsg, int &nMsgLen,int nMsgType,int &nReceiveCount)=0;
};
RabbitMQ.h
#pragma once
#include "MiddleWareConnection.h"
#include "Amqp.h"
#pragma comment(lib, "rabbitmq.4.lib")
#define GET_DATA(a){memcpy(&a, pDataPtr, sizeof(a));pDataPtr+=sizeof(a);}
#define GET_DATA_EX(s,n){memcpy(s, pDataPtr, n);pDataPtr+=n;}
typedef struct _ROUTINE_KEY
{
CString RoutingKey;
}ROUTEKEY, *LPROUTEKEY;
class CRabbitMQ :
public CMiddleWareConnection
{
public:
CRabbitMQ(CAppConfig &rConfig);
~CRabbitMQ();
void InitializeRBMQ(CAppConfig &rConfig);//Initialize RBMQ Config;
BOOL Connect(int nServerType);
BOOL Disconnect(void);
BOOL Send(void *MomItem, LPCTSTR lpszKey, int &nSendCount);
BOOL Receive(void);
BOOL CreateQueue(LPCTSTR lpszQueueName);
BOOL CreateSessionExchange();
BOOL BindQueue(LPCTSTR lpszQueue, LPCTSTR lpszExchangeName, LPCTSTR lpszKey);
bool IsConnected(){return m_bConnected;}
void SetKeyQueueCombination( TCHAR *pszQueueName, TCHAR *pszRoutingKey);
void StopReceiver();
bool ReEstablishRMQMWConnection();
void GetData(LPBYTE &pMsg, int &nMsgLen,int &nReceiveCount);
void GetData(void* pMsg, int &nMsgLen,int nMsgType,int &nReceiveCount);
BOOL GetNext_JasonListItem(LPJASON_ITEM pItem);
LPRABBIT_MQ_ITEM GetNextItem();
};
Here I want to show the functions of the rabbitMq class [Connect, Send, Get ete from MiddleWareConnection.h in C #.
thank
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3 answers
below I posted a small sample code for a C ++ / CLI class. You can create a new C ++ / CLI project that will link your own library and create the following class. This will create a managed assembly that you could reference from the C # side. Hope this helps!
#include <Windows.h>
#include <vcclr.h>
using namespace System;
using namespace System::Text;
using namespace System::Collections::Generic;
using namespace System::Runtime::InteropServices;
public ref class CMiddleWareConnection_Net
{
public:
CMiddleWareConnection_Net()
{
pMiddleWareConnection = NULL;
}
~CMiddleWareConnection_Net()
{
//Release pMiddleWareConnection
if (pMiddleWareConnection)
delete pMiddleWareConnection;
}
void InitializeRBMQ(CAppConfig_Net config)
{
// CAppConfig_Net is another ref class
// which provides a toNative method
// returning a plain C++ CAppConfig object
CAppConfig rConfig = config.toNative();
pMiddleWareConnection = CRabbitMQ(rConfig);
}
bool Connect(int nServerType)
{
return (pMiddleWareConnection->Connect(nServerType) == TRUE);
}
bool Disconnect(void)
{
return (pMiddleWareConnection->Disconnect() == TRUE);
}
bool Send(array<Byte>^ MomItem, String^ lpszKey, int% nSendCount)
{
//Assuming MomItem is a byte array...
unsigned char *pData = new unsigned char[MomItem->Length];
Marshal::Copy(MomItem, 0, IntPtr(pData), MomItem->Length);
//Marshal String^ to LPCSTR
IntPtr ip = Marshal::StringToHGlobalAnsi(lpszKey);
LPCSTR str = static_cast<LPCSTR>(ip.ToPointer());
bool bRet = (pMiddleWareConnection->Send(pData, str, nSendCount) == TRUE);
//Freeing memory
delete[] pData;
Marshal::FreeHGlobal(ip);
return bRet;
}
bool Receive(void)
{
return (pMiddleWareConnection->Receive() == TRUE);
}
/* Other methods */
...
private:
CMiddleWareConnection *pMiddleWareConnection;
};
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**** MiddleWareFactory.h ****
BOOL CreateInstance(CMiddleWareConnection** pMObj)
{
//if( some config value)
*pMObj = new RabbitMq();
// esle
/***other MOm like OBCS,OSCS etec...**/
}
**** **** MiddlewareConnection.h
have the basic abstract functions....
**Rabbitmq.h**
it is one of the child class.
**** **** Packing
CLRWrapper::CppMathWrapper::CppMathWrapper()
{
cppMath = new cCppMath();
oFact->createInstance(&cppMath);'// here i want to pass the reference & wanna get back the child class type:now i am stuck here..how can we pass/marshal the object:im getting the error
}
BOOL CLRWrapper::CppMathWrapper::connect(type)
{
return (cppMath->Connect(nServerType) == TRUE);
}
..........And so On............
CLR Wrapper.cpp (11): error C2664: 'Factory :: createInstance': cannot convert parameter 1 from 'cli :: interior_ptr' to 'Base **' 1> with 1> [1> Type = cCppMath * 1> ] 1> Cannot convert managed type to unmanaged type
}
instead we use createinstance () . [InitializeRBMQ () is inside connect (), so it will be handled internally I guess]
void InitializeRBMQ(CAppConfig_Net config)
{
// CAppConfig_Net is another ref class
// which provides a toNative method
// returning a plain C++ CAppConfig object
CAppConfig rConfig = config.toNative();
pMiddleWareConnection = CRabbitMQ(rConfig);
}
C # side I want to expose:
private static void Main(string[] args)
{
CppMathWrapper wrapper = new CppMathWrapper();
wrapper.connect(0);
}
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I tried one example with the CPPMath class. In reality, I am adding the code below:
CLRWrapper::CppMathWrapper::CppMathWrapper()
{
middlewareConnection *oConn;// MiddleConnection.h pointer
middleWareFactory oFact= new middleWareFactory ();// MiddleWareFactory.h object
oFact->createInstance(&oConn);'// here i want to pass the reference & wanna get back the child class type:now i am stuck here..how can we pass/marshal the object:im getting the error.How could i wrap the object....the same like
}
BOOL CLRWrapper::CppMathWrapper::connect(type)
{
return (oConn->Connect(nServerType) == TRUE);
}
..........And so On............
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