VC/VB 进行图像数据存储数据库心得[1]

【无忧考网 - VC】
VC/VB 进行图像数据存储数据库心得
　　网上经常有人问如何把图像存入数据库中，原先我也是不得要领。经过多方指点和自己在开发过程中的摸索，终于解决这一问题。下面给出用VC，VB如何操作图像文件存取数据库的原码，帮助一些还没有掌握方法的朋友（均用ADO连接数据库）。

一、VC把一个文件存入数据库
CFile imagefile; if(0 == imagefile.Open("d:\\user\\bmp.bmp",CFile::modeRead)) return; _RecordsetPtr pRs = NULL; _ConnectionPtr pConnection = NULL; _variant_t varChunk; HRESULT hr; BYTE* pbuf; long nLength = imagefile.GetLength(); pbuf = new BYTE[nLength+2]; if(pbuf == NULL) return; //allocate memory error; imagefile.Read(pbuf,nLength); //read the file into memory BYTE *pBufEx; pBufEx = pbuf; //build a SAFFERRAY SAFEARRAY* psa; SAFEARRAYBOUND rgsabound[1]; rgsabound[0].lLbound = 0; rgsabound[0].cElements = nLength; psa = SafeArrayCreate(VT_UI1, 1, rgsabound); for (long i = 0; i < nLength; i++) SafeArrayPutElement (psa, &i, pBufEx++); VARIANT varBLOB; varBLOB.vt = VT_ARRAY | VT_UI1; varBLOB.parray = psa; _bstr_t strCnn("Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=CUSTOM;Data Source=SERVER"); try { //Open a connection pConnection.CreateInstance(__uuidof(Connection)); hr = pConnection->Open(strCnn,"","",NULL); //Connect a DataBase pRs.CreateInstance(__uuidof(Recordset)); pRs->Open("CustomInfo",_variant_t((IDispatch *) pConnection,true),adOpenKeyset,adLockOptimistic,adCmdTable); //Open a Table // pRs->AddNew(); pRs->Fields->GetItem("Image")->AppendChunk(varBLOB); pRs->Update(); pRs->Close(); pConnection->Close(); } catch(_com_error &e) { // Notify the user of errors if any. _bstr_t bstrSource(e.Source()); _bstr_t bstrDescription(e.Description()); CString sError; sError.Format("Source : %s \n Description : %s\n",(LPCSTR)bstrSource,(LPCSTR)bstrDescription); AfxMessageBox(sError); }

　　 二、VC把数据库中IMAGE字段取出存为文件
_RecordsetPtr pRs = NULL; _ConnectionPtr pConnection = NULL; _variant_t varChunk; HRESULT hr; VARIANT varBLOB; _bstr_t strCnn("Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=CUSTOM;Data SoVC