vs2010 MFC DLL创建和调用02

进一步再举一例:本例要实现一个绘制一个椭圆形功能

<1> : 根据前一篇"vs2010 MFC DLL创建和调用"文章新建MFC Dll工程,假设工程名CMFCDLLDemo02;

<2> : 在CMFCDLLDemo02.h中添加:

#include "resource.h"  // main symbols

// CCMFCDLLDemo02App
// See CMFCDLLDemo02.cpp for the implementation of this class
//
extern "C" void PASCAL EXPORT DrawEllipse( CRect rect, CDC *pDC );
class CCMFCDLLDemo02App : public CWinApp
{
public:
 CCMFCDLLDemo02App();

// Overrides
public:
 virtual BOOL InitInstance();

 DECLARE_MESSAGE_MAP()
};

<3> : 然后在CMFCDLLDemo02.cpp中添加函数体:

extern "C" void PASCAL EXPORT DrawEllipse( CRect rect, CDC *pDC)
{
 CBrush brush;
 brush.CreateSolidBrush(RGB(0,0,255));
 pDC->SelectObject(&brush);
 pDC->Ellipse(&rect);
}

<4> : def文件配置:

; CMFCDLLDemo02.def : Declares the module parameters for the DLL.

LIBRARY "MFCDLLDEMO"

EXPORTS
    ; Explicit exports can go here
 DrawEllipse

<5> : ->build CMFCDLLDemo02工程,既可以.

<6> : 调用MFCDLLDEMO.dll,新建工程一个MFC工程(假设单文档工程吧).

<7> : 在视窗view的OnDraw函数中增加:

void CMFCApView::OnDraw(CDC* pDC)
{
   // DLL MFC Library function call
   CRect rect;
   rect.top=10;
   rect.left=10;
   rect.right=200;
   rect.bottom=200; 
   DrawEllipse(rect,pDC); 

   // DLL class object call
   int a, b, c;
   CString str;
   DLLclass classFromDLL; 
   classFromDLL.Arg = 6; 
   a = classFromDLL.Add(3, 2);
   b = classFromDLL.Sub(3, 2);
   c = classFromDLL.Arg;

   // Display data in window
   int y = 250, dy;
   TEXTMETRIC tm;
   pDC->GetTextMetrics(&tm);
   dy = tm.tmHeight + tm.tmExternalLeading; 
   str.Format("DLL class Add function return: %d", a);
   pDC->TextOut(20, y, str);
   y += dy;
   str.Format("DLL class Sub function return: %d", b);
   pDC->TextOut(20, y, str);
   y += dy;
   str.Format("DLL class Arg Variable return: %d", c);
   pDC->TextOut(20, y, str);
   y += dy; 
   a = DLLArg;
   b = DLLfun2(30); 
   str.Format("DLL class Arg Variable return: %d", a);
   pDC->TextOut(20, y, str);
   y += dy;
   str.Format("DLL function \"DLLfun2\" return: %d", b);
   pDC->TextOut(20, y, str);
}

<8> 编译运行,既可以看见椭圆体图形.