accessmdbdlg.cpp

在VC下访问和创建Access数据库的例子

// AccessMdbDlg.cpp : implementation file
//

#include "stdafx.h"
#include "AccessMdb.h"
#include "AccessMdbDlg.h"
#include <stdlib.h>

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// 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()

/////////////////////////////////////////////////////////////////////////////
// CAccessMdbDlg dialog

CAccessMdbDlg::CAccessMdbDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CAccessMdbDlg::IDD, pParent)
{
	//{{AFX_DATA_INIT(CAccessMdbDlg)
	m_Name = _T("");
	m_Age = _T("");
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CAccessMdbDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CAccessMdbDlg)
	DDX_Control(pDX, IDC_LIST1, m_AccessList);
	DDX_Text(pDX, IDC_EDIT_NAME, m_Name);
	DDX_Text(pDX, IDC_EDIT_AGE, m_Age);
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAccessMdbDlg, CDialog)
	//{{AFX_MSG_MAP(CAccessMdbDlg)
	ON_WM_SYSCOMMAND()
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_READ, OnRead)
	ON_BN_CLICKED(IDC_EXIT, OnExit)
	ON_BN_CLICKED(IDC_INSERT, OnInsert)
	ON_BN_CLICKED(IDC_MODIFY, OnModify)
	ON_BN_CLICKED(IDC_DELETE, OnDelete)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CAccessMdbDlg message handlers

BOOL CAccessMdbDlg::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
	m_pConnection == NULL;
	m_pRecordset = NULL;
//	::CoInitialize(NULL); //初始化OLE/COM库环境

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

void CAccessMdbDlg::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 CAccessMdbDlg::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 CAccessMdbDlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}

void CAccessMdbDlg::OnRead() 
{
	// TODO: Add your control notification handler code here
	// 初始化COM,创建ADO连接等操作

	if(m_pConnection == NULL){
		AfxOleInit();
		m_pConnection.CreateInstance(__uuidof(Connection));	

		try
		{

		// 打开本地Access库Demo.mdb
		m_pConnection->Open("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=../Demo.mdb",""
			,"",adModeUnknown);
		}
		catch(_com_error e)
		{
			AfxMessageBox("数据库连接失败，确认数据库Demo.mdb是否在当前路径下!");
			return;
		}
	}

	// 打开数据表
/*	if(m_pRecordset == NULL){
		m_pRecordset.CreateInstance(__uuidof(Recordset));
		try{
			m_pRecordset->Open("SELECT * FROM DemoTable", // 查询DemoTable表中所有字段
			m_pConnection.GetInterfacePtr(), // 获取库接库的IDispatch指针
			adOpenDynamic,
			adLockOptimistic,
			adCmdText);
		}
	
		catch(_com_error *e){
			AfxMessageBox(e->ErrorMessage());
		}
	}
*/

	_CommandPtr m_pCommand;
	m_pCommand.CreateInstance(__uuidof(Command));
	m_pCommand->ActiveConnection = m_pConnection; // 将库连接赋于它
	m_pCommand->CommandText = "SELECT * FROM DemoTable"; // SQL语句
	m_pRecordset = m_pCommand->Execute(NULL, NULL,adCmdText); // 执行SQL语句，返回记录集

	DisplayData();
}


void CAccessMdbDlg::DisplayData()
{
	// 读取表内数据
	_variant_t var;
	CString strName,strAge;
	try{
		if(!m_pRecordset->BOF)
			m_pRecordset->MoveFirst();
		else{
			AfxMessageBox("表内数据为空");
			return;
		}

		m_AccessList.ResetContent();

		// 读入库中各字段并加入列表框中
		while(!m_pRecordset->adoEOF)
		{
			var = m_pRecordset->GetCollect("Name");
			if(var.vt != VT_NULL)
			strName = (LPCSTR)_bstr_t(var);
			var = m_pRecordset->GetCollect("Age");
			if(var.vt != VT_NULL)
				strAge = (LPCSTR)_bstr_t(var);
			m_AccessList.AddString( strName + " --> "+strAge );
			m_pRecordset->MoveNext();
		}

		// 默认列表指向第一项，同时移动记录指针并显示
		m_AccessList.SetCurSel(0);
	}


	catch(_com_error *e){
		AfxMessageBox(e->ErrorMessage());
	}
}

void CAccessMdbDlg::OnExit() 
{
	// TODO: Add your control notification handler code here
	if(m_pConnection != NULL && m_pConnection->State)
		m_pConnection->Close();
	m_pConnection= NULL;
	OnCancel();
}

void CAccessMdbDlg::OnInsert() 
{
	// TODO: Add your control notification handler code here
	UpdateData(TRUE);

	if(m_pConnection == NULL || m_pConnection == NULL){
		AfxMessageBox("No connection");
		return;
	}


	try
	{
		// 写入各字段值
		m_pRecordset->AddNew();
		m_pRecordset->PutCollect("Name", _variant_t(m_Name));
//		m_pRecordset->PutCollect("Age", m_Age);
		m_pRecordset->PutCollect("Age", atol(m_Age));
		m_pRecordset->Update();
		AfxMessageBox("插入成功!");
	}
	catch(_com_error *e)
	{
		AfxMessageBox(e->ErrorMessage());
	}
	
	DisplayData();
}

void CAccessMdbDlg::OnModify() 
{
	// TODO: Add your control notification handler code here
	UpdateData(TRUE);
	int n_Item = m_AccessList.GetCurSel();

	try
	{
		m_pRecordset->MoveFirst();
		for(int i = 0; i < n_Item; i++){
			m_pRecordset->MoveNext();
		}
		m_pRecordset->PutCollect("Name", _variant_t(m_Name));
		m_pRecordset->PutCollect("Age", atol(m_Age));
		m_pRecordset->Update();
	}

	catch(_com_error *e)
	{
		AfxMessageBox(e->ErrorMessage());
	}	

	DisplayData();
}

void CAccessMdbDlg::OnDelete() 
{
	// TODO: Add your control notification handler code here
	UpdateData(TRUE);
	int n_Item = m_AccessList.GetCurSel();

	try
	{
		m_pRecordset->MoveFirst();
		for(int i = 0; i < n_Item; i++){
			m_pRecordset->MoveNext(); // 从0开始
		}

		m_pRecordset->Delete(adAffectCurrent); // 参数adAffectCurrent为删除当前记录
		m_pRecordset->Update();
	}

	catch(_com_error *e)
	{
		AfxMessageBox(e->ErrorMessage());
	}	

	DisplayData();
}