使用ado實(shí)現(xiàn)vc中二進(jìn)制文件數(shù)據(jù)的存取

1、使用使用ADO實(shí)現(xiàn)實(shí)現(xiàn)vc中二進(jìn)制文件數(shù)據(jù)的存取（以圖像在數(shù)據(jù)庫(kù)中的存取為中二進(jìn)制文件數(shù)據(jù)的存取（以圖像在數(shù)據(jù)庫(kù)中的存取為例）例）實(shí)現(xiàn)方法簡(jiǎn)述關(guān)鍵代碼如下：1、保存圖片數(shù)據(jù)到數(shù)據(jù)庫(kù)、保存圖片數(shù)據(jù)到數(shù)據(jù)庫(kù)以下是代碼片段：1.JPG圖片保存到數(shù)據(jù)庫(kù)2.try3.4._RecdsetPtrpRecdset5.pRecdset.CreateInstance(__uuidof(Recdset))6.pRecdsetOpen(“FROMjpg“_v

2、ariant_t((IDispatch)pConnection)adOpenStaticadLockOptimisticadCmdText)7.pRecdsetAddNew()8.pRecdsetFieldsItem[“jpgid“]Value=(_variant_t)m_JPGIdjpgid9.VARIANTpvList10.SetPictureToVariant(pvList(unsigned)m_pJPGBuffer)11.pRe

3、cdsetFieldsItem[“jpgimage“]AppendChunk(pvList)JPG圖像文件12.VariantClear(13.14.pRecdsetUpdate()15.pRecdsetClose()16.AfxMessageBox(“JPG圖像保存成功！“)17.m_JPGId==““18.UpdateData(false)19.20.catch(...)21.22.AfxMessageBox(“數(shù)據(jù)庫(kù)讀取失敗“)2

4、3.return24.其中SetPictureToVariant如下：以下是代碼片段：1.voidCBMPinDBDlg::SetPictureToVariant(VARIANT21.longlDataSize=pRecdsetGetFields()GetItem(“jpgimage“)ActualSize22.m_nFileLen=(DWD)lDataSize23.if(lDataSize0)24.25._variant_tvarBL

5、OB26.varBLOB=pRecdsetGetFields()GetItem(“jpgimage“)GetChunk(lDataSize)27.把二進(jìn)制格式的圖片轉(zhuǎn)為圖片格式28.try29.30.if(varBLOB.vt==(VT_ARRAY|VT_UI1))31.32.if(m_pJPGBuffer=new[lDataSize1])33.34.pBuf=NULL35.SafeArrayAccessData(varBLOB.par

6、ray(void)36.memcpy(m_pJPGBufferpBuflDataSize)37.SafeArrayUnaccessData(varBLOB.parray)38.m_nFileLen=lDataSize39.40.m_pJPGBufferpPicture41.HGLOBALhMem=::GlobalAlloc(GMEM_MOVEABLEm_nFileLen)42.LPVOIDlpBuf=::GlobalLock(hMem)