C++ 不正确不需要重新声明 class 成员变量 MFC handmade solution/project MS VS 2015

Question

我试图缩短一个外国代码。我想我可以保存一个变量。

下面给出的代码是正确的，并显示了一个 Windows 帧。

#include <afxwin.h> 
// from source: http://www.codersource.net/2010/01/30/mfc-tutorial-part-1/
class MFC_Tutorial_Window :public CFrameWnd
{
public:
    MFC_Tutorial_Window()    
    {
        Create(NULL, "MFC Tutorial Part 1 CoderSource Window");  
    }
};

class MyApp :public CWinApp
{
    MFC_Tutorial_Window *wnd;  

public:
    BOOL InitInstance()
    {
        wnd = new MFC_Tutorial_Window();
        m_pMainWnd = wnd;                        
        m_pMainWnd->ShowWindow(1);
        return 1;
    }
};

MyApp theApp;

在我改写后它不再起作用了。没有构建错误。但它不显示框架。

#include <afxwin.h> 
// from source: http://www.codersource.net/2010/01/30/mfc-tutorial-part-1/
// and changed by me

class MFC_Tutorial_Window :public CFrameWnd
{
public:
    MFC_Tutorial_Window()
    {
        Create(NULL, "MFC Tutorial Part 1 CoderSource Window");
    }
};

class MyApp :public CWinApp
{
    // del MFC_Tutorial_Window *wnd;
    MFC_Tutorial_Window *m_pMainWnd; // ins 


public:
    BOOL InitInstance()
    {
        // del wnd = new MFC_Tutorial_Window();
        // del m_pMainWnd = wnd;
        m_pMainWnd = new MFC_Tutorial_Window(); // ins
        m_pMainWnd->ShowWindow(1);
        return 1;
    }
};

MyApp theApp;

怎么了？

Answer 1

问题出在成员变量MFC_Tutorial_Window *m_pMainWnd;的重新声明中，没有这一行它会起作用。

C++ 不正确不需要重新声明 class 成员变量 MFC handmade solution/project MS VS 2015

C++ uncorrect not required re-declaring of class member variable MFC handmade solution/project MS VS 2015

c++

mfc

pointers

typing

window-handles