MFC 动态dll调用函数编码实现

一、
1.先打开Microsoft Visual Studio 2010软件。
2.点击新建项目->选择MFC DLL，在名称处填写“DllTest”，点击确定。
3.点击下一步->选择“使用共享MFC DLL的规则 DLL”，点击完成。
4.在“DllTest.h”文件中，添加extern “C” __declspec(dllexport)bool add(int a,int b,int *c);语句。
5.在“DllTest.def”文件中，在输入add。
6.在“DllTest.cpp”文件中，添加如下语句：

extern "C" __declspec(dllexport)bool add(int a,int b,int *c)
{
*c=a+b;

return true;
}

修改后的这三个文件为：

DllTest.h

// DllTest.h : main header file for the DllTest DLL
//

#pragma once

#ifndef __AFXWIN_H__
	#error "include 'stdafx.h' before including this file for PCH"
#endif

#include "resource.h"		// main symbols


// CDllTestApp
// See DllTest.cpp for the implementation of this class
//

class CDllTestApp : public CWinApp
{
public:
	CDllTestApp();

// Overrides
public:
	virtual BOOL InitInstance();

	DECLARE_MESSAGE_MAP()
};

extern "C" __declspec(dllexport)bool add(int a,int b,int *c);

DllTest.def

; DllTest.def : Declares the module parameters for the DLL.

LIBRARY

EXPORTS
    ; Explicit exports can go here

	add
	

DllTest.cpp

// DllTest.cpp : Defines the initialization routines for the DLL.
//

#include "stdafx.h"
#include "DllTest.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

//
//TODO: If this DLL is dynamically linked against the MFC DLLs,
//        any functions exported from this DLL which call into
//        MFC must have the AFX_MANAGE_STATE macro added at the
//        very beginning of the function.
//
//        For example:
//
//        extern "C" BOOL PASCAL EXPORT ExportedFunction()
//        {
//            AFX_MANAGE_STATE(AfxGetStaticModuleState());
//            // normal function body here
//        }
//
//        It is very important that this macro appear in each
//        function, prior to any calls into MFC.  This means that
//        it must appear as the first statement within the 
//        function, even before any object variable declarations
//        as their constructors may generate calls into the MFC
//        DLL.
//
//        Please see MFC Technical Notes 33 and 58 for additional
//        details.
//

// CDllTestApp

BEGIN_MESSAGE_MAP(CDllTestApp, CWinApp)
END_MESSAGE_MAP()


// CDllTestApp construction

CDllTestApp::CDllTestApp()
{
    // TODO: add construction code here,
    // Place all significant initialization in InitInstance
}


// The one and only CDllTestApp object

CDllTestApp theApp;


// CDllTestApp initialization

BOOL CDllTestApp::InitInstance()
{
    CWinApp::InitInstance();

    return TRUE;
}


extern "C" __declspec(dllexport)bool add(int a,int b,int *c)
{
    *c=a+b;

    return true;
} 

编译生成DllTest.dll

 

二、再新建一个基于对话框的工程，再ok按钮事件函数中添加如下代码：

void CCreateThreadDlg::SetEditText(CString strText)
{
    GetDlgItem(IDC_EDIT1)->SetWindowText(strText);
}


void CCreateThreadDlg::OnBnClickedOk()
{
    // TODO: Add your control notification handler code here
    //CDialogEx::OnOK();


    HINSTANCE hPro= ::LoadLibrary("DllTest.dll");
    if(hPro == NULL)
    {
        return;
    }
    else
    {
        typedef bool (*DLL_ADD)( int a,int b,int *c);
        DLL_ADD dllAddFunc = NULL;
        dllAddFunc=(DLL_ADD)::GetProcAddress(hPro, "add");

        if(dllAddFunc)
        {
            int s= 0;
            dllAddFunc(8,4,&s);

            CString strSum;
            strSum.Format("%d", s);

            SetEditText(strSum);
            
        }
        ::FreeLibrary(hPro);
    }
}

再把DllTest.dll复制到测试工程的exe同级目录，然后编译、运行，对话框中的输入框值为12