单例模式简易模板

class TableDlg : public CDialogEx
{
    DECLARE_DYNAMIC(TableDlg)

public:
    TableDlg(CWnd* pParent = nullptr);   // 标准构造函数
    virtual ~TableDlg();

// 对话框数据
#ifdef AFX_DESIGN_TIME
    enum { IDD = IDD_TABLE_DIALOG };
#endif

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

    DECLARE_MESSAGE_MAP()
public:

    //获取单例，只允许当前创建一个对象
    static TableDlg* GetTableDlg();

private:
    //只能实例化一个类
    static TableDlg* m_pTableDlg;
};

TableDlg* TableDlg::m_pTableDlg = nullptr;

// TableDlg 对话框

IMPLEMENT_DYNAMIC(TableDlg, CDialogEx)

TableDlg::TableDlg(CWnd* pParent /*=nullptr*/)
    : CDialogEx(IDD_TABLE_DIALOG, pParent)
{
    Create(IDD_TABLE_DIALOG);
}

TableDlg::~TableDlg()
{
}

void TableDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialogEx::DoDataExchange(pDX);
}


BEGIN_MESSAGE_MAP(TableDlg, CDialogEx)
END_MESSAGE_MAP()

TableDlg* TableDlg::GetTableDlg()
{
    if (!m_pTableDlg)
    {
        m_pTableDlg = new TableDlg;
    }
    return m_pTableDlg;
}

    TableDlg *nTableDlg = TableDlg::GetTableDlg();