成员变量 - 未定义和不可访问

Posted 2023-02-16

【中文标题】成员变量 - 未定义和不可访问

【英文标题】：Member Variables - Undefined and Inaccessible

【发布时间】：2013-04-05 21:15:22

【问题描述】：

我无法从成员函数CAboutDlg::OnLButtonDown 访问私有成员变量。 当我尝试为 ellipseColor 分配一个新值时，我得到了undeclared identifier 错误。当我尝试通过它的类CCSIT861a3VasilkovskiyDlg::ellipseColor访问它时，编译器说它是不可访问的。

我错过了什么，如何访问/修改这些变量？

头文件：

#pragma once


// CCSIT861a3VasilkovskiyDlg dialog
class CCSIT861a3VasilkovskiyDlg : public CDialogEx

// Construction
public:
    CCSIT861a3VasilkovskiyDlg(CWnd* pParent = NULL);    // standard constructor

// Dialog Data
    enum  IDD = IDD_CSIT861A3VASILKOVSKIY_DIALOG ;

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


// Implementation
protected:
    HICON m_hIcon;

    // Generated message map functions
    virtual BOOL OnInitDialog();
    afx_msg void OnSysCommand(UINT nID, LPARAM lParam);
    afx_msg void OnPaint();
    afx_msg HCURSOR OnQueryDragIcon();
    DECLARE_MESSAGE_MAP()
private:
    COLORREF ellipseColor;
    COLORREF centerRectColor;
    COLORREF rightRectColor;
    CRect centerRect;
    CRect rightRect;
    CSize ellipse;
    bool mouseCaptured;
;

实施文件：

#include "stdafx.h"
#include "CSIT861a3 Vasilkovskiy.h"
#include "CSIT861a3 VasilkovskiyDlg.h"
#include "afxdialogex.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// CAboutDlg dialog used for App About

class CAboutDlg : public CDialogEx

public:
    CAboutDlg();

// Dialog Data
    enum  IDD = IDD_ABOUTBOX ;

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

// Implementation
protected:
    DECLARE_MESSAGE_MAP()
public:
    afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
    afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
    afx_msg void OnMouseMove(UINT nFlags, CPoint point);
;

CAboutDlg::CAboutDlg() : CDialogEx(CAboutDlg::IDD)



void CAboutDlg::DoDataExchange(CDataExchange* pDX)

    CDialogEx::DoDataExchange(pDX);


BEGIN_MESSAGE_MAP(CAboutDlg, CDialogEx)
    ON_WM_LBUTTONDOWN()
    ON_WM_LBUTTONUP()
    ON_WM_MOUSEMOVE()
END_MESSAGE_MAP()


// CCSIT861a3VasilkovskiyDlg dialog




CCSIT861a3VasilkovskiyDlg::CCSIT861a3VasilkovskiyDlg(CWnd* pParent /*=NULL*/)
    : CDialogEx(CCSIT861a3VasilkovskiyDlg::IDD, pParent)

    m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);

    ellipseColor = RGB(255, 0, 0);
    centerRectColor = RGB(0, 0, 0);
    rightRectColor = RGB(255, 0, 0);
    centerRect.left = 40;
    centerRect.top = 20;
    centerRect.right = 55;
    centerRect.bottom = 80;
    rightRect.left = 75;
    rightRect.top = 35;
    rightRect.right = 90;
    rightRect.bottom = 50;
    ellipse.cx = 10;
    ellipse.cy = 10;
    mouseCaptured = false;


void CCSIT861a3VasilkovskiyDlg::DoDataExchange(CDataExchange* pDX)

    CDialogEx::DoDataExchange(pDX);


BEGIN_MESSAGE_MAP(CCSIT861a3VasilkovskiyDlg, CDialogEx)
    ON_WM_SYSCOMMAND()
    ON_WM_PAINT()
    ON_WM_QUERYDRAGICON()
END_MESSAGE_MAP()


// CCSIT861a3VasilkovskiyDlg message handlers

BOOL CCSIT861a3VasilkovskiyDlg::OnInitDialog()

    CDialogEx::OnInitDialog();

    // Add "About..." menu item to system menu.

    // IDM_ABOUTBOX must be in the system command range.
    ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
    ASSERT(IDM_ABOUTBOX < 0xF000);

    CMenu* pSysMenu = GetSystemMenu(FALSE);
    if (pSysMenu != NULL)
    
        BOOL bNameValid;
        CString strAboutMenu;
        bNameValid = strAboutMenu.LoadString(IDS_ABOUTBOX);
        ASSERT(bNameValid);
        if (!strAboutMenu.IsEmpty())
        
            pSysMenu->AppendMenu(MF_SEPARATOR);
            pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
        
    

    // Set the icon for this dialog.  The framework does this automatically
    //  when the application's main window is not a dialog
    SetIcon(m_hIcon, TRUE);         // Set big icon
    SetIcon(m_hIcon, FALSE);        // Set small icon

    // TODO: Add extra initialization here

    return TRUE;  // return TRUE  unless you set the focus to a control


void CCSIT861a3VasilkovskiyDlg::OnSysCommand(UINT nID, LPARAM lParam)

    if ((nID & 0xFFF0) == IDM_ABOUTBOX)
    
        CAboutDlg dlgAbout;
        dlgAbout.DoModal();
    
    else
    
        CDialogEx::OnSysCommand(nID, lParam);
    


// If you add a minimize button to your dialog, you will need the code below
//  to draw the icon.  For MFC applications using the document/view model,
//  this is automatically done for you by the framework.

void CCSIT861a3VasilkovskiyDlg::OnPaint()

    //Create pen and pointer to the old pen
    CPen blackPen; 
    blackPen.CreatePen(PS_SOLID, 1, RGB (0, 0, 0)); 

    //Create a bursh
    CBrush blackBrush(centerRectColor);
    CBrush redBrush(rightRectColor);
    CBrush hatchRedBrush(HS_CROSS, ellipseColor);

    //Set up object for painting
    CPaintDC dc (this);
    CRect rect;
    GetClientRect (&rect);
    dc.SetMapMode (MM_ANISOTROPIC);
    dc.SetWindowExt (100, 100);
    dc.SetViewportExt (rect.Width (), rect.Height ());


    //select pen 
    dc.SelectObject(&blackPen);

    //Rectangle red interior color
    dc.SelectObject(&redBrush);
    dc.Rectangle(rightRect); //(75, 35, 90, 50);

    //Rectangel black interior
    dc.SelectObject(&blackBrush);//Select Brush
    dc.Rectangle( centerRect);//(40, 20, 55, 80);

    //Ellipse
    dc.SelectObject(&hatchRedBrush);//Select Brush
    dc.Ellipse(ellipse.cx, ellipse.cy, (ellipse.cx) + 10, (ellipse.cy) + 10);//10, 10, 20, 20);

    if (IsIconic())
    
        CPaintDC dc(this); // device context for painting

        SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

        // Center icon in client rectangle
        int cxIcon = GetSystemMetrics(SM_CXICON);
        int cyIcon = GetSystemMetrics(SM_CYICON);
        CRect rect;
        GetClientRect(&rect);
        int x = (rect.Width() - cxIcon + 1) / 2;
        int y = (rect.Height() - cyIcon + 1) / 2;

        // Draw the icon
        dc.DrawIcon(x, y, m_hIcon);
    
    else
    
        CDialogEx::OnPaint();
    


// The system calls this function to obtain the cursor to display while the user drags
//  the minimized window.
HCURSOR CCSIT861a3VasilkovskiyDlg::OnQueryDragIcon()

    return static_cast<HCURSOR>(m_hIcon);




void CAboutDlg::OnLButtonDown(UINT nFlags, CPoint point)

    // TODO: Add your message handler code here and/or call default
    //SetCapture();
    CClientDC dc(this);
    CRect rect;
    GetClientRect(&rect);
    dc.SetMapMode(MM_ANISOTROPIC);
    dc.SetWindowExt(100, 100);
    dc.SetViewportExt(rect.Width(), rect.Height());
    CRect rectEllipse(10, 10, 20, 20);



    CDialogEx::OnLButtonDown(nFlags, point);



void CAboutDlg::OnLButtonUp(UINT nFlags, CPoint point)

    // TODO: Add your message handler code here and/or call default
    ReleaseCapture ();
    CDialogEx::OnLButtonUp(nFlags, point);



void CAboutDlg::OnMouseMove(UINT nFlags, CPoint point)

    // TODO: Add your message handler code here and/or call default

    CDialogEx::OnMouseMove(nFlags, point);

【参考方案1】：

您的OnLButtonDown() 是CAboutDlg 的成员函数，但您正试图访问private 的非static 数据成员CCSIT861a3VasilkovskiyDlg，这是一个不同班级。

您可能打算将函数 OnLButtonDown()、OnLButtonUp() 和 OnMouseMove() 作为 CCSIT861a3VasilkovskiyDlg 的成员函数，而不是作为 CAboutDlg 的成员函数。