< SQL SERVER 2000 案例教程>>,冶金工业出版社,这本书的代码

				// 售货系统Dlg.cpp : implementation file
				//
				
				#include "stdafx.h"
				#include "售货系统.h"
				#include "售货系统Dlg.h"
				
				#ifdef _DEBUG
				#define new DEBUG_NEW
				#undef THIS_FILE
				static char THIS_FILE[] = __FILE__;
				#endif
				extern CDatabase m_database;
				extern CString username;
				extern CString userpower;
				extern CMainDlg* maindlg;
				/////////////////////////////////////////////////////////////////////////////
				// CAboutDlg dialog used for App About
				
				class CAboutDlg : public CDialog
				{
				public:
					CAboutDlg();
				
				// Dialog Data
					//{{AFX_DATA(CAboutDlg)
					enum { IDD = IDD_ABOUTBOX };
					//}}AFX_DATA
				
					// ClassWizard generated virtual function overrides
					//{{AFX_VIRTUAL(CAboutDlg)
					protected:
					virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support
					//}}AFX_VIRTUAL
				
				// Implementation
				protected:
					//{{AFX_MSG(CAboutDlg)
					//}}AFX_MSG
					DECLARE_MESSAGE_MAP()
				};
				
				CAboutDlg::CAboutDlg() : CDialog(CAboutDlg::IDD)
				{
					//{{AFX_DATA_INIT(CAboutDlg)
					//}}AFX_DATA_INIT
				}
				
				void CAboutDlg::DoDataExchange(CDataExchange* pDX)
				{
					CDialog::DoDataExchange(pDX);
					//{{AFX_DATA_MAP(CAboutDlg)
					//}}AFX_DATA_MAP
				}
				
				BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)
					//{{AFX_MSG_MAP(CAboutDlg)
						// No message handlers
					//}}AFX_MSG_MAP
				END_MESSAGE_MAP()
				
				/////////////////////////////////////////////////////////////////////////////
				// CMyDlg dialog
				
				CMyDlg::CMyDlg(CWnd* pParent /*=NULL*/)
					: CDialog(CMyDlg::IDD, pParent)
				{
					//{{AFX_DATA_INIT(CMyDlg)
					m_password = _T("");
					m_user = _T("");
					//}}AFX_DATA_INIT
					// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
					m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
				}
				
				void CMyDlg::DoDataExchange(CDataExchange* pDX)
				{
					CDialog::DoDataExchange(pDX);
					//{{AFX_DATA_MAP(CMyDlg)
					DDX_Text(pDX, IDC_PASSWORD, m_password);
					DDX_Text(pDX, IDC_USER, m_user);
					//}}AFX_DATA_MAP
				}
				
				BEGIN_MESSAGE_MAP(CMyDlg, CDialog)
					//{{AFX_MSG_MAP(CMyDlg)
					ON_WM_SYSCOMMAND()
					ON_WM_PAINT()
					ON_WM_QUERYDRAGICON()
					ON_BN_CLICKED(IDLOGIN, OnLogin)
					//}}AFX_MSG_MAP
				END_MESSAGE_MAP()
				
				/////////////////////////////////////////////////////////////////////////////
				// CMyDlg message handlers
				
				BOOL CMyDlg::OnInitDialog()
				{
					CDialog::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)
					{
						CString strAboutMenu;
						strAboutMenu.LoadString(IDS_ABOUTBOX);
						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 CMyDlg::OnSysCommand(UINT nID, LPARAM lParam)
				{
					if ((nID & 0xFFF0) == IDM_ABOUTBOX)
					{
						CAboutDlg dlgAbout;
						dlgAbout.DoModal();
					}
					else
					{
						CDialog::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 CMyDlg::OnPaint() 
				{
					if (IsIconic())
					{
						CPaintDC dc(this); // device context for painting
				
						SendMessage(WM_ICONERASEBKGND, (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
					{
						CDialog::OnPaint();
					}
				}
				
				// The system calls this to obtain the cursor to display while the user drags
				//  the minimized window.
				HCURSOR CMyDlg::OnQueryDragIcon()
				{
					return (HCURSOR) m_hIcon;
				}
				
				void CMyDlg::OnLogin() 
				{
					CString sql;
					UpdateData(true);//把各控件的内容更新到各自对应的控件中
					CUserSet m_userset;
					if(!m_database.IsOpen()){
						try{//连接数据库
							m_database.Open(_T("售货系统"),false,false,_T("ODBC;UID=sa;UPASSWORD="),true);
						}catch(CDBException e1){
							MessageBox("Can`t connect the database");
						}
						catch(CMemoryException e2){
							MessageBox("Can`t connect the database");
						}
					} 
					//sql保存SQL语句，用于读到数据库中的数据
					sql.Format("select * from 用户密码表 where 用户名='%s' and 用户密码='%s'",m_user,m_password);
					m_userset.m_pDatabase=&m_database;
					//使用Open函数执行SQL语句
					m_userset.Open(AFX_DB_USE_DEFAULT_TYPE,sql);
					//当读到的数据为空时，则输出提示语句
					if(m_userset.IsEOF()){
						MessageBox("数据库里没有相应资料，请检查用户名密码是否正确");
						m_user="";
						m_password="";
					}else{
						//读取数据成功，则进行赋值，并进行其他操作
						username.Format("%s",m_userset.m_column1);
						username.TrimLeft();//消除空格
						username.TrimRight();
						userpower=m_userset.m_column3;
						userpower.TrimLeft();
						userpower.TrimRight();
					 	maindlg->ShowWindow(SW_SHOW);//显示主窗口
						maindlg->m_sheet.Show();//显示tab control控件内容
						CDialog::OnOK();
					 	//ShowWindow(SW_HIDE);//隐藏登录对话框
					}
					UpdateData(FALSE);//把变量值反映在文本框里
					
				}
				
				void CMyDlg::OnCancel() 
				{
					exit(0);//退出程序
				}