How do I call an instance method from an exported method in a MFC DLL?

[arnoldw]

I have created a dll in MFC using the Visual Studio wizard and the dll exports a function called MyExportedMethod:

#include "stdafx.h"
#include "DllProblem.h"

BEGIN_MESSAGE_MAP(CDllProblemApp, CWinApp)
END_MESSAGE_MAP()

CDllProblemApp::CDllProblemApp()
{
}

CDllProblemApp theApp;

BOOL CDllProblemApp::InitInstance()
{
CWinApp::InitInstance();
return TRUE;
}

double _stdcall MyExportedMethod(double param)
{
// Here I would like to call the
// MethodIwouldLikeToInvoke method in class MyClass.
// How do I do that???

return 0;
}

I would like the MyExportedMethod method to invoke a (non-static) method in a class called MyClass:

#include "stdafx.h"
#include "DllProblem.h"
#include "MyClass.h"

IMPLEMENT_DYNAMIC(MyClass, CDialog)

MyClass::MyClass(CWnd* pParent /*=NULL*/): CDialog(MyClass::IDD, pParent)
{
}

MyClass::~MyClass()
{
}

void MyClass:oDataExchange(CDataExchange* pDX)
{
CDialog:oDataExchange(pDX);
}

BEGIN_MESSAGE_MAP(MyClass, CDialog)
END_MESSAGE_MAP()

void MyClass::MethodIwouldLikeToInvoke()
{
MessageBox(L"Congratulations! The exported method successfully invoked the correct method!");
}

What should I add to successfully invoke the MethodIwouldLikeToInvoke from the MyExportedMethod method? This may seem like a simple problem and that is ok, this is not a trick question (I'm a beginner C++ programmer). Thank you in advance!

 

[bnbertha]

You can't call a non-static method without a pointer to the instance of the class containing the method. The best way of doing this is to use a static method to return a pointer for the class instantiation you want to call. If you only want one instance of MyClass running try making MyClass conform to the Singleton design pattern.

Bertha

 

[arnoldw]

Thanks for your reply. I solved it like this:

class CDllProblemApp...
{
...
MyClass myInstance;
...
};


double _stdcall MyExportedMethod(double param)
{
theApp.myInstance.MethodIwouldLikeToInvoke();
return 0;
}