往数据库中添加照片

        pRecordSet.CreateInstance(__uuidof(Recordset));
        strCmd.Format(
            _T("SELECT * FROM 班级表%d order by 学号 "),
            m_pParentStudentInfo->m_nClassID);
        pRecordSet->Open((_variant_t)strCmd,m_pConnection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
    
        pRecordSet->AddNew();
        pRecordSet->PutCollect(_T("学号"),(long)nXuehao);
        pRecordSet->PutCollect(_T("姓名"),(LPCTSTR)nameStr);
        pRecordSet->PutCollect(_T("地址"),(LPCTSTR)addStr);
        pRecordSet->PutCollect(_T("联系方式"),(LPCTSTR)lianxiStr);
        pRecordSet->PutCollect(_T("备注"),(LPCTSTR)beizhuStr);
        CFile f;
        CFileException e;
        if(f.Open(zhaoPianStr, CFile::modeRead | CFile::typeBinary, &e)) //打开了一个jpg文件
        {    
            int nSize = f.GetLength();          //先得到jpg文件长度
            BYTE * pBuffer = new BYTE [nSize];  //按文件的大小在堆上申请一块内存
            if (f.Read(pBuffer, nSize) > 0 )    //把jpg文件读到pBuffer(堆上申请一块内存)
            { 
                BYTE *pBuf = pBuffer;     ///下面这一大段是把pBuffer里的jpg数据放到库中
                VARIANT            varBLOB;
                SAFEARRAY        *psa;
                SAFEARRAYBOUND    rgsabound[1];
                if(pBuf)
                {    
                    rgsabound[0].lLbound = 0;
                    rgsabound[0].cElements = nSize;
                    psa = SafeArrayCreate(VT_UI1, 1, rgsabound);
                    for (long i = 0; i < (long)nSize; i++)
                        SafeArrayPutElement (psa, &i, pBuf++);
                    varBLOB.vt = VT_ARRAY | VT_UI1;
                    varBLOB.parray = psa;
                    pRecordSet->GetFields()->GetItem(_T("照片"))->AppendChunk(varBLOB);
                }
            
                delete []pBuffer;
                pBuf=NULL;
            }
            f.Close ();
        }
        pRecordSet->Update();

读取照片

   CString    xuehaoStr=m_XueShengList.GetItemText(nIndex,0); //选中行的第一列的文字
    _CommandPtr spCmd;
    _RecordsetPtr pRecordSet;
    spCmd.CreateInstance(__uuidof(Command));
    spCmd->ActiveConnection=m_pConnection;
    CString strCmd;
    strCmd.Format(
        _T("select * from  班级表%d where 学号=%d"),
        m_pParentStudentInfo->m_nClassID,
        _ttoi(xuehaoStr));
    spCmd->CommandText=(LPCTSTR)strCmd;
    pRecordSet=spCmd->Execute (NULL,NULL,adCmdText);
    if (pRecordSet->adoEOF) //未找到此学号的学生
        return;
    if(m_Pic.m_IPicture != NULL) m_Pic.FreePictureData();
            
    long nSize=pRecordSet->GetFields()->GetItem(_T("照片"))->ActualSize;
    if(nSize>0)
    {
        _variant_t varBLOB;
        varBLOB=pRecordSet->GetFields()->GetItem(_T("照片"))->GetChunk(nSize);
        
        if (varBLOB.vt==(VT_ARRAY|VT_UI1))
        {
            if (BYTE* pBuffer=new BYTE[nSize+1])
            {
                char *pBuf=NULL;
                SafeArrayAccessData(varBLOB.parray,(void**)&pBuf);
                memcpy(pBuffer,pBuf,nSize);
                SafeArrayUnaccessData(varBLOB.parray);
                m_Pic.LoadPictureData(pBuffer,nSize);
                delete [] pBuffer;
                pBuf=NULL;
            
            //PICTURE控件 自动适应大小
            m_Photo.GetClientRect (rc);
            m_Photo.ClientToScreen(rc);
            ScreenToClient(rc);
            long Width  = 0;
            long Height = 0;
            m_Pic.m_IPicture->get_Width(&Width);
            m_Pic.m_IPicture->get_Height(&Height);
            float f=Width/(float)Height;
            long w=f*(rc.bottom-rc.top);
            m_Photo.SetWindowPos (NULL,rc.left,rc.top,w,rc.Height(), SWP_NOMOVE);
            m_Photo.GetClientRect (rc);
            CClientDC dc(&m_Photo);
            m_Pic.UpdateSizeOnDC (&dc);
            rc.left--;
            rc.top--;
            m_Pic.Show (&dc,rc);
            }
        }
    }