急！急！急！用vc如何把数据库中的jpeg文件读出并在视图中显示出来?

[xiaohyy]

1。jpeg在数据库中是否以二进制方式存储？
2。若是以二进制方式存储，读出时怎样在视图上显示？
我知道一种读数据库中位图的方法，读出来后显示是用CreateDIBitmap函数得到HBITMAP.但是显示jpeg又怎样做呢？？

还望哪位大虾指点，不甚感激！！

[mfkzj]

1.是
2。void CShowJpgView::OnDraw(CDC* pDC)
{
CShowJpgDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
if(m_ok==false)
{
IStream *pStm;
CFileStatus fstatus;
CFile file;
LONG cb;
if (file.Open("test.jpg",CFile::modeRead)&&file.GetStatus("test.jpg",fstatus)&&
((cb = fstatus.m_size) != -1))
{
HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, cb);
LPVOID pvData = NULL;
if (hGlobal != NULL)
{
if ((pvData = GlobalLock(hGlobal)) != NULL)
{
file.ReadHuge(pvData, cb);
GlobalUnlock(hGlobal);
CreateStreamOnHGlobal(hGlobal, TRUE, &pStm);

if(SUCCEEDED(OleLoadPicture(pStm,fstatus.m_size,TRUE,IID_IPicture,(LPVOID*)&pPic)))
{
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;

pPic->get_Width(&hmWidth);
pPic->get_Height(&hmHeight);

// double fX,fY;
// fX = (double)pDC->GetDeviceCaps(HORZRES)*(double)hmWidth/((double)pDC->GetDeviceCaps(HORZSIZE)*100.0);
// fY = (double)pDC->GetDeviceCaps(VERTRES)*(double)hmHeight/((double)pDC->GetDeviceCaps(VERTSIZE)*100.0);
// if(FAILED(pPic->Render(*pDC,0,0,(DWORD)fX,(DWORD)fY,0,hmHeight,hmWidth,-hmHeight,NULL)))
double fX,fY;
fX = 640;
fY = 480;
if(FAILED(pPic->Render(*pDC,0,0,(DWORD)fX,(DWORD)fY,0,hmHeight,hmWidth,-hmHeight,NULL)))
AfxMessageBox("Failed To Render The picture!");
// pPic->Release();
m_ok=true;
}
else
AfxMessageBox("Error Loading Picture From Stream!");
}
}
}
else
AfxMessageBox("Can't Open Image File!");
}
else
{
OLE_XSIZE_HIMETRIC hmWidth;
OLE_YSIZE_HIMETRIC hmHeight;
pPic->get_Width(&hmWidth);
pPic->get_Height(&hmHeight);
double fX,fY;
fX = 640;
fY = 480;
pPic->Render(*pDC,0,0,(DWORD)fX,(DWORD)fY,0,hmHeight,hmWidth,-hmHeight,NULL);
}
// TODO: add draw code for native data here
}

[CharmDream]

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