在一个MFC EXE项目中继承MFC扩展项目中的类

[rr12]

在MFC扩展DLL中，CDialog1从CDialog派生，并有一个对话框资源。

在使用该扩展DLL的MFC EXE项目中，CDialog2从CDialog1派生。

生成时：

Error 1 error LNK2001: unresolved external symbol "public: static struct CRuntimeClass const CDialog1::classCDialog1" (?classCDialog1@CDialog1@@2UCRuntimeClass@@B) Dialog2.obj ExtDll_2_tester




代码：

Dialog1.h:


#pragma once

#include "resource.h"


// CDialog1 dialog

class __declspec(dllexport) CDialog1 : public CDialog
{
DECLARE_DYNAMIC(CDialog1)

public:
CDialog1(CWnd* pParent = NULL); // standard constructor
virtual ~CDialog1();

// Dialog Data
enum { IDD = IDD_DIALOG1 };

protected:
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support

DECLARE_MESSAGE_MAP()
};





// Dialog1.cpp : implementation file
//

#include "stdafx.h"
#include "Dialog1.h"


// CDialog1 dialog

IMPLEMENT_DYNAMIC(CDialog1, CDialog)

CDialog1::CDialog1(CWnd* pParent /*=NULL*/)
: CDialog(CDialog1::IDD, pParent)
{

}

CDialog1::~CDialog1()
{
}

void CDialog1::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
}


BEGIN_MESSAGE_MAP(CDialog1, CDialog)
END_MESSAGE_MAP()


// CDialog1 message handlers




Dialog2.h:


#pragma once

#include "Dialog1.h"
#pragma comment(lib,"ExtDll_2.lib")

// CDialod2

class CDialog2 : public CDialog1
{
DECLARE_DYNAMIC(CDialog2)

public:
CDialog2();
virtual ~CDialog2();

protected:
DECLARE_MESSAGE_MAP()
};





// Dialod2.cpp : implementation file
//

#include "stdafx.h"
#include "ExtDll_2_tester.h"
#include "Dialog2.h"

#include "Dialog1.h"
#pragma comment(lib,"ExtDll_2.lib")

// CDialod2

IMPLEMENT_DYNAMIC(CDialog2, CDialog1)

CDialog2::CDialog2()
{

}

CDialog2::~CDialog2()
{
}


BEGIN_MESSAGE_MAP(CDialog2, CDialog1)
END_MESSAGE_MAP()



// CDialod2 message handlers






MFC EXE项目中引入的Dialog1.h:


#pragma once

#include "resource.h"

#pragma comment(lib,"ExtDll_2.lib")

// CDialog1 dialog

class CDialog1 : public CDialog
{
DECLARE_DYNAMIC(CDialog1)

public:
CDialog1(CWnd* pParent = NULL); // standard constructor
virtual ~CDialog1();

// Dialog Data
// enum { IDD = IDD_DIALOG1 };

protected:
virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support

DECLARE_MESSAGE_MAP()
};

[运动健将]

ExtDll_2_tester里面可能没引用那个报错的函数吧.h文件

[cpp2017]

这个class要标记为导出．

[晒月光的青蛙]

头文件肯定是引用的，这是个未知符号错误，看看有没有把dll的lib加入到工程中，或者添加到工程linker-》Input-》Additional Dependency中