An MFC extension library to enable DLL plug-in technology for your application using MESSAGE_MAPs

// AppPlugInCore.cpp : Defines the class behaviors for the application.
//

#include "stdafx.h"
#include <afxdllx.h>

#include "AppPlugInCore.h"

#include "MainFrm.h"
#include "ChildFrm.h"
#include "AppPlugInCoreDoc.h"
#include "AppPlugInCoreView.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CAppPlugInCoreApp

BEGIN_MESSAGE_MAP(CAppPlugInCoreApp, CPlugInApp)
	//{{AFX_MSG_MAP(CAppPlugInCoreApp)
	ON_COMMAND(ID_APP_ABOUT, OnAppAbout)
		// NOTE - the ClassWizard will add and remove mapping macros here.
		//    DO NOT EDIT what you see in these blocks of generated code!
	//}}AFX_MSG_MAP
	// Standard file based document commands
	ON_COMMAND(ID_FILE_NEW, CPlugInApp::OnFileNew)
	ON_COMMAND(ID_FILE_OPEN, CPlugInApp::OnFileOpen)
	// Standard print setup command
	ON_COMMAND(ID_FILE_PRINT_SETUP, CPlugInApp::OnFilePrintSetup)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CAppPlugInCoreApp construction

CAppPlugInCoreApp::CAppPlugInCoreApp()
{
}

/////////////////////////////////////////////////////////////////////////////
// The one and only CAppPlugInCoreApp object

CAppPlugInCoreApp theApp;

/////////////////////////////////////////////////////////////////////////////
// CAppPlugInCoreApp initialization

BOOL CAppPlugInCoreApp::InitInstance()
{
	AfxEnableControlContainer();

	// Standard initialization
	// If you are not using these features and wish to reduce the size
	//  of your final executable, you should remove from the following
	//  the specific initialization routines you do not need.

#ifdef _AFXDLL
	Enable3dControls();			// Call this when using MFC in a shared DLL
#else
	Enable3dControlsStatic();	// Call this when linking to MFC statically
#endif

	// Change the registry key under which our settings are stored.
	// TODO: You should modify this string to be something appropriate
	// such as the name of your company or organization.
	SetRegistryKey(_T("Plug-In Example application"));

	LoadStdProfileSettings();  // Load standard INI file options (including MRU)

	// Load the plug-in DLL's.
	// This needs to be done before any document templates are registered and before the mainframe is created
	// as the plug-in DLL's can hook the mainframe message. Creation is a required message to hook
	// to allow additional toolbars and floating windows etc to be added.
	LoadPlugInDLLs() ;
	ReplaceDocManager() ;

	// Register the application's document templates.  Document templates
	// serve as the connection between documents, frame windows and views.

	CMyMultiDocTemplate* pDocTemplate;
	pDocTemplate = new CMyMultiDocTemplate(
		IDR_APPPLUTYPE,
		RUNTIME_CLASS(CAppPlugInCoreDoc),
		RUNTIME_CLASS(CChildFrame),
		RUNTIME_CLASS(CAppPlugInCoreView));
	AddDocTemplate(pDocTemplate);

	// now register any plug-in DLL document templates
	RegisterDLLDocumentTemplates() ;

	// create main MDI Frame window
	CMainFrame* pMainFrame = new CMainFrame;
	if (!pMainFrame->LoadFrame(IDR_MAINFRAME))
		return FALSE;
	m_pMainWnd = pMainFrame;
	UpdateMenus() ;
	UpdateAccelerators() ;
	InitialisePlugIns() ;

	// Parse command line for standard shell commands, DDE, file open
	CCommandLineInfo cmdInfo;
	ParseCommandLine(cmdInfo);

	// Dispatch commands specified on the command line
	if (!ProcessShellCommand(cmdInfo))
		return FALSE;

	// The main window has been initialized, so show and update it.
	pMainFrame->ShowWindow(m_nCmdShow);
	pMainFrame->UpdateWindow();

	return TRUE;
}


/////////////////////////////////////////////////////////////////////////////
// CAboutDlg dialog used for App About

class CAboutDlg : public CDialog
{
public:
	CAboutDlg();

// Dialog Data
	//{{AFX_DATA(CAboutDlg)
	enum { IDD = IDD_ABOUTBOX };
	//}}AFX_DATA

	// ClassWizard generated virtual function overrides
	//{{AFX_VIRTUAL(CAboutDlg)
	protected:
	virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support
	//}}AFX_VIRTUAL

// Implementation
protected:
	//{{AFX_MSG(CAboutDlg)
		// No message handlers
	//}}AFX_MSG
	DECLARE_MESSAGE_MAP()
};

CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
{
	//{{AFX_DATA_INIT(CAboutDlg)
	//}}AFX_DATA_INIT
}

void CAboutDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CAboutDlg)
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
	//{{AFX_MSG_MAP(CAboutDlg)
		// No message handlers
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

// App command to run the dialog
void CAppPlugInCoreApp::OnAppAbout()
{
	CAboutDlg aboutDlg;
	aboutDlg.DoModal();
}

/////////////////////////////////////////////////////////////////////////////
// CAppPlugInCoreApp message handlers


int CAppPlugInCoreApp::ExitInstance() 
{
	return CPlugInApp::ExitInstance();
}

static AFX_EXTENSION_MODULE PlugInLibraryDLL = { NULL, NULL };

extern "C" int APIENTRY
DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved)
{
	// Remove this if you use lpReserved
	UNREFERENCED_PARAMETER(lpReserved);

	if (dwReason == DLL_PROCESS_ATTACH)
	{
		TRACE0("PLUGINLIBRARY.DLL Initializing!\n");
		
		// Extension DLL one-time initialization
		if (!AfxInitExtensionModule(PlugInLibraryDLL, hInstance))
			return 0;

		// Insert this DLL into the resource chain
		// NOTE: If this Extension DLL is being implicitly linked to by
		//  an MFC Regular DLL (such as an ActiveX Control)
		//  instead of an MFC application, then you will want to
		//  remove this line from DllMain and put it in a separate
		//  function exported from this Extension DLL.  The Regular DLL
		//  that uses this Extension DLL should then explicitly call that
		//  function to initialize this Extension DLL.  Otherwise,
		//  the CDynLinkLibrary object will not be attached to the
		//  Regular DLL's resource chain, and serious problems will
		//  result.

		new CDynLinkLibrary(PlugInLibraryDLL);
	}
	else if (dwReason == DLL_PROCESS_DETACH)
	{
		TRACE0("PLUGINLIBRARY.DLL Terminating!\n");
		// Terminate the library before destructors are called
		AfxTermExtensionModule(PlugInLibraryDLL);
	}
	return 1;   // ok
}