Visual C++多线程DAO处理

如果没有上面的定义的话，你的应用程序就会出问题。整个DAO公共函数并没有全部实现，但不管怎么样，上面的函数是保护CDaoRecordset的使用的。如果你要加个函数的话，加进去就行了，你也可以用一个对话框来显示错误信息，它们都应该在MultiDaorecordset.h中被定义。为了支持DAO多线程的类，下面的代码也应该加进去：

加在Multidaorecordset.cpp中：

// MultiDaoRecordSet.cpp : implementation file

//

#define MULTIDAORECORDSET_CPP

#include "stdafx.h"

#include "MyApp.h"

#include "MultiDaoRecordSet.h"

#include "mainfrm.h"

#ifdef _DEBUG

#define new DEBUG_NEW

#undef THIS_FILE

static char THIS_FILE[] = __FILE__;

#endif

/////////////////////////////////////////////////////////////////////////////

// CMultiDaoRecordSet

IMPLEMENT_DYNAMIC(CMultiDaoRecordSet, CDaoRecordset)

CMultiDaoRecordSet::CMultiDaoRecordSet(CDaoDatabase* pdb)

: CDaoRecordset(pdb)

{

//{{AFX_FIELD_INIT(CMultiDaoRecordSet)

//}}AFX_FIELD_INIT

m_nDefaultType = dbOpenDynaset;

}

//jtm

//thread safe destructor....

CMultiDaoRecordSet::~CMultiDaoRecordSet()

{

if (IsOpen())

Close();

// Clean up database if necessary

if (m_pDatabase != NULL && (m_nStatus & AFX_DAO_IMPLICIT_DB))

{

m_pDatabase->Close();

delete m_pDatabase;

m_pDatabase = NULL;

}

}

CString CMultiDaoRecordSet::GetDefaultDBName()

{

CMyApp *pApp = ((CMYApp *)AfxGetApp());

return pApp->GetDatabaseFullPath();

}

/////////////////////////////////////////////////////////////////////////////

// CMultiDaoRecordSet diagnostics

//jtm

//multi thread safe functoins

void CMultiDaoRecordSet::Open(int nOpenType, LPCTSTR lpszSQL, int nOptions)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::Open(nOpenType, lpszSQL, nOptions);

}

else

{

pParam1 = (void *)&nOpenType;

pParam2 = (void *)lpszSQL;

pParam3 = (void *)&nOptions;

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoOpen, (LPARAM)this);

}

}

void CMultiDaoRecordSet::Close()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::Close();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoClose, (LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::IsOpen()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::IsOpen();

}

else

{

return (BOOL)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoIsOpen, (LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::IsBOF()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::IsBOF();

}

else

{

return (BOOL)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoIsBOF, (LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::IsEOF()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::IsEOF();

}

else

{

return (BOOL)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoIsEOF, (LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::IsDeleted()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::IsDeleted();

}

else

{

return (BOOL)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoIsDeleted, (LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::IsFieldDirty(void* pv)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::IsFieldDirty(pv);

}

else

{

pParam1 = pv;

return (BOOL)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoIsFieldDirty, (LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::IsFieldNull(void* pv)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::IsFieldNull(pv);

}

else

{

pParam1 = pv;

return (BOOL)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoIsFieldNull, (LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::IsFieldNullable(void* pv)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::IsFieldNullable(pv);

}

else

{

pParam1 = pv;

return (BOOL)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoIsFieldNullable, (LPARAM)this);

}

}

CString CMultiDaoRecordSet::GetName()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::GetName();

}

else

{

return (CString)*(CString *)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoGetName, (LPARAM)this);

}

}

short CMultiDaoRecordSet::GetType()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::GetType();

}

else

{

return (short)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoGetType, (LPARAM)this);

}

}

short CMultiDaoRecordSet::GetEditMode()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::GetEditMode();

}

else

{

return (short)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoGetEditMode, (LPARAM)this);

}

}

CString CMultiDaoRecordSet::GetSQL()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::GetSQL();

}

else

{

return (CString)*(CString *)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoGetSQL, (LPARAM)this);

}

}

COleVariant CMultiDaoRecordSet::GetLastModifiedBookmark()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::GetLastModifiedBookmark();

}

else

{

return (COleVariant)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoGetLastModifiedBookmark, (LPARAM)this);

}

}

long CMultiDaoRecordSet::GetRecordCount()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::GetRecordCount();

}

else

{

return (long)AfxGetMainWnd()->

SendMessage(WM_MULTIDAOMESSAGE, MultiDaoGetRecordCount, (LPARAM)this);

}

}

void CMultiDaoRecordSet::MoveNext()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::MoveNext();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoMoveNext,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::MovePrev()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::MovePrev();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoMovePrev,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::MoveFirst()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::MoveFirst();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoMoveFirst,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::MoveLast()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::MoveLast();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoMoveLast,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::Move(long lRows)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::Move(lRows);

}

else

{

pParam1 = (void *)&lRows;

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoMove,

(LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::FindNext(LPCTSTR lpszFilter)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::FindNext(lpszFilter);

}

else

{

pParam1 = (void *)lpszFilter;

return (BOOL)AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoFindNext,

(LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::FindPrev(LPCTSTR lpszFilter)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::FindPrev(lpszFilter);

}

else

{

pParam1 = (void *)lpszFilter;

return (BOOL)AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoFindPrev,

(LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::FindFirst(LPCTSTR lpszFilter)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::FindFirst(lpszFilter);

}

else

{

pParam1 = (void *)lpszFilter;

return (BOOL)AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoFindFirst,

(LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::FindLast(LPCTSTR lpszFilter)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::FindLast(lpszFilter);

}

else

{

pParam1 = (void *)lpszFilter;

return (BOOL)AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoFindLast,

(LPARAM)this);

}

}

BOOL CMultiDaoRecordSet::Find(long lFindType, LPCTSTR lpszFilter)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::Find(lFindType, lpszFilter);

}

else

{

pParam1 = (void *)&lFindType;

pParam2 = (void *)lpszFilter;

return (BOOL)AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoFind,

(LPARAM)this);

}

}

COleVariant CMultiDaoRecordSet::GetBookmark()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

return CDaoRecordset::GetBookmark();

}

else

{

return AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoGetBookmark,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::SetBookmark(COleVariant varBookmark)

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::SetBookmark(varBookmark);

}

else

{

pParam1 = (void *)&varBookmark;

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoSetBookmark,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::AddNew()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::AddNew();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoAddNew,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::Edit()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::Edit();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoEdit,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::Update()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::Update();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoUpdate,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::Delete()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::Delete();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoDelete,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::CancelUpdate()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::CancelUpdate();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoCancelUpdate,

(LPARAM)this);

}

}

void CMultiDaoRecordSet::Requery()

{

CMYApp *pApp = ((CMYApp *)AfxGetApp());

if (pApp->pGUIThread == AfxGetThread())

{

CDaoRecordset::Requery();

}

else

{

AfxGetMainWnd()->SendMessage(WM_MULTIDAOMESSAGE, MultiDaoRequery,

(LPARAM)this);

}

}

and, Multidaorecordset.h

#if !defined(AFX_MULTIDAORECORDSET_H__BECC8DC3_A967_11D2_BA4C_006097808646__INCLUDED_)

#define AFX_MULTIDAORECORDSET_H__BECC8DC3_A967_11D2_BA4C_006097808646__INCLUDED_

#if _MSC_VER >= 1000

#pragma once

#endif // _MSC_VER >= 1000

// MultiDaoRecordSet.h : header file

//

/////////////////////////////////////////////////////////////////////////////

// CMultiDaoRecordSet DAO recordset

enum {

MultiDaoOpen,

MultiDaoClose,

MultiDaoIsOpen,

MultiDaoIsBOF,

MultiDaoIsEOF,

MultiDaoIsDeleted,

MultiDaoIsFieldDirty,

MultiDaoIsFieldNull,

MultiDaoIsFieldNullable,

MultiDaoGetName,

MultiDaoGetType,

MultiDaoGetSQL,

MultiDaoGetEditMode,

MultiDaoGetLastModifiedBookmark,

MultiDaoGetRecordCount,

MultiDaoMoveNext,

MultiDaoMovePrev,

MultiDaoMoveFirst,

MultiDaoMoveLast,

MultiDaoMove,

MultiDaoFindNext,

MultiDaoFindPrev,

MultiDaoFindFirst,

MultiDaoFindLast,

MultiDaoFind,

MultiDaoGetBookmark,

MultiDaoSetBookmark,

MultiDaoAddNew,

MultiDaoEdit,

MultiDaoUpdate,

MultiDaoDelete,

MultiDaoCancelUpdate,

MultiDaoRequery,

};

#ifdef MULTIDAORECORDSET_CPP

CString cDAOMessageArray[] =

{

"MultiDaoOpen",

"MultiDaoClose",

"MultiDaoIsOpen",

"MultiDaoIsBOF",

"MultiDaoIsEOF",

"MultiDaoIsDeleted",

"MultiDaoIsFieldDirty",

"MultiDaoIsFieldNull",

"MultiDaoIsFieldNullable",

"MultiDaoGetName",

"MultiDaoGetType",

"MultiDaoGetSQL",

"MultiDaoGetEditMode",

"MultiDaoGetLastModifiedBookmark",

"MultiDaoGetRecordCount",

"MultiDaoMoveNext",

"MultiDaoMovePrev",

"MultiDaoMoveFirst",

"MultiDaoMoveLast",

"MultiDaoMove",

"MultiDaoFindNext",

"MultiDaoFindPrev",

"MultiDaoFindFirst",

"MultiDaoFindLast",

"MultiDaoFind",

"MultiDaoGetBookmark",

"MultiDaoSetBookmark",

"MultiDaoAddNew",

"MultiDaoEdit",

"MultiDaoUpdate",

"MultiDaoDelete",

"MultiDaoCancelUpdate",

"MultiDaoRequery",

};

#else

extern CString cDAOMessageArray[];

#endif

class CMultiDaoRecordSet : public CDaoRecordset

{

public:

//jtm

//FORCE user to pass database...

CMultiDaoRecordSet(CDaoDatabase* pDatabase);

~CMultiDaoRecordSet();

DECLARE_DYNAMIC(CMultiDaoRecordSet)

// Field/Param Data

//{{AFX_FIELD(CMultiDaoRecordSet, CDaoRecordset)

//}}AFX_FIELD

// Overrides

// ClassWizard generated virtual function overrides

//{{AFX_VIRTUAL(CMultiDaoRecordSet)

public:

virtual CString GetDefaultDBName(); // Default database name

//}}AFX_VIRTUAL

// Implementation

//jtm

//redefined public functions

//Note: I am only redefining SOME

//of the public functions this is NOT

//a FULL implementation !!!!!!

public:

//jtm -- only supporting this open.....

virtual void Open(int nOpenType = AFX_DAO_USE_DEFAULT_TYPE,

LPCTSTR lpszSQL = NULL, int nOptions = 0);

virtual void Close();

BOOL IsOpen();

BOOL IsBOF();

BOOL IsEOF();

BOOL IsDeleted();

BOOL IsFieldDirty(void* pv);

BOOL IsFieldNull(void* pv);

BOOL IsFieldNullable(void* pv);

CString GetName();

short GetType();

short GetEditMode();

CString GetSQL();

COleVariant GetLastModifiedBookmark();

long GetRecordCount();

void MoveNext();

void MovePrev();

void MoveFirst();

void MoveLast();

virtual void Move(long lRows);

BOOL FindNext(LPCTSTR lpszFilter);

BOOL FindPrev(LPCTSTR lpszFilter);

BOOL FindFirst(LPCTSTR lpszFilter);

BOOL FindLast(LPCTSTR lpszFilter);

virtual BOOL Find(long lFindType, LPCTSTR lpszFilter);

COleVariant GetBookmark();

void SetBookmark(COleVariant varBookmark);

virtual void AddNew();

virtual void Edit();

virtual void Update();

virtual void Delete();

virtual void CancelUpdate();

virtual void Requery();

void *pParam1;

void *pParam2;

void *pParam3;

};

//{{AFX_INSERT_LOCATION}}

// Microsoft Developer Studio will insert additional declarations immediately before the //previous line.

#endif // !defined(AFX_MULTIDAORECORDSET_H__BECC8DC3_A967_11D2_BA4C_006097808646__INCLUDED_)

调试的东西等你搞好你的程序后就可以删了，不过要注意，不要直接调用CDaoRecordset，否则，你的应用程序就会问题。我试了一下，使用这个类的时候，你的计算机的速度会稍微的暂停几秒钟(正在运行你的程序)，不过这不会影响到你的计算机的使用的，因为这个类DAO的调用是通过GUI的，如果你使用不当的话(比如临界区问题)就会导致计算机的死锁。

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