数据库编程

开发平台：
Visual C++

ImageDBView.cpp：源码内容
							// ImageDBView.cpp : implementation of the CImageDBView class
//
#include "stdafx.h"
#include "ImageDB.h"
#include "ImageDBDoc.h"
#include "ImageDBView.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
/////////////////////////////////////////////////////////////////////////////
// CImageDBView
IMPLEMENT_DYNCREATE(CImageDBView, CFormView)
BEGIN_MESSAGE_MAP(CImageDBView, CFormView)
	//{{AFX_MSG_MAP(CImageDBView)
	ON_BN_CLICKED(IDC_BUTTON1, OnButton1)
	ON_BN_CLICKED(IDC_BUTTON2, OnButton2)
	ON_BN_CLICKED(IDC_BUTTON3, OnButton3)
	//}}AFX_MSG_MAP
	// Standard printing commands
	ON_COMMAND(ID_FILE_PRINT, CFormView::OnFilePrint)
	ON_COMMAND(ID_FILE_PRINT_DIRECT, CFormView::OnFilePrint)
	ON_COMMAND(ID_FILE_PRINT_PREVIEW, CFormView::OnFilePrintPreview)
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CImageDBView construction/destruction
CImageDBView::CImageDBView()
	: CFormView(CImageDBView::IDD)
{
	//{{AFX_DATA_INIT(CImageDBView)
		// NOTE: the ClassWizard will add member initialization here
	//}}AFX_DATA_INIT
	// TODO: add construction code here
	m_bDraw=0;
	m_bImageOpen=FALSE;
}
CImageDBView::~CImageDBView()
{
}
void CImageDBView::DoDataExchange(CDataExchange* pDX)
{
	CFormView::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CImageDBView)
		// NOTE: the ClassWizard will add DDX and DDV calls here
	//}}AFX_DATA_MAP
}
BOOL CImageDBView::PreCreateWindow(CREATESTRUCT& cs)
{
	// TODO: Modify the Window class or styles here by modifying
	//  the CREATESTRUCT cs
	return CFormView::PreCreateWindow(cs);
}
void CImageDBView::OnInitialUpdate()
{
	CFormView::OnInitialUpdate();
	GetParentFrame()->RecalcLayout();
	ResizeParentToFit();
}
/////////////////////////////////////////////////////////////////////////////
// CImageDBView printing
BOOL CImageDBView::OnPreparePrinting(CPrintInfo* pInfo)
{
	// default preparation
	return DoPreparePrinting(pInfo);
}
void CImageDBView::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
	// TODO: add extra initialization before printing
}
void CImageDBView::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
	// TODO: add cleanup after printing
}
void CImageDBView::OnPrint(CDC* pDC, CPrintInfo* /*pInfo*/)
{
	// TODO: add customized printing code here
}
/////////////////////////////////////////////////////////////////////////////
// CImageDBView diagnostics
#ifdef _DEBUG
void CImageDBView::AssertValid() const
{
	CFormView::AssertValid();
}
void CImageDBView::Dump(CDumpContext& dc) const
{
	CFormView::Dump(dc);
}
CImageDBDoc* CImageDBView::GetDocument() // non-debug version is inline
{
	ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CImageDBDoc)));
	return (CImageDBDoc*)m_pDocument;
}
#endif //_DEBUG
/////////////////////////////////////////////////////////////////////////////
// CImageDBView message handlers
void CImageDBView::OnButton1() 
{
	// TODO: Add your control notification handler code here
	CString sPno,sPname;
	GetDlgItemText(IDC_EDIT1,sPno);
	GetDlgItemText(IDC_EDIT2,sPname);
	if (sPno.IsEmpty())
	{
		AfxMessageBox("请输入球员号！");
		GetDlgItem(IDC_EDIT1)->SetFocus();
		return;
	}
	if (sPname.IsEmpty())
	{
		AfxMessageBox("请输入球员名字！");
		GetDlgItem(IDC_EDIT2)->SetFocus();
		return;
	}
	if (!m_bImageOpen)
	{
		AfxMessageBox("请选择球员图片");
		GetDlgItem(IDC_BUTTON3)->SetFocus();
		return;
	}
	_RecordsetPtr pRecordset;
	pRecordset.CreateInstance(__uuidof(Recordset));
	CString strSQL;
	strSQL.Format("select * from Player where Pno='%s'",sPno);
	pRecordset->Open(_variant_t(strSQL),GetDocument()->m_pConnection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
	if (!pRecordset->BOF)
	{
		AfxMessageBox("您要输入的球员号已存在！");
		pRecordset->Close();
		return;
	}
	pRecordset->Close();
	strSQL.Format("insert into Player values('%s','%s',0x)",sPno,sPname);	
	pRecordset->Open(_variant_t(strSQL),GetDocument()->m_pConnection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
	strSQL.Format("select Photo from player where Pno='%s'",sPno);
	pRecordset->Open(_variant_t(strSQL),GetDocument()->m_pConnection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
	Image_DB(TRUE,m_FileName,pRecordset,"Photo");
	pRecordset->Close();
	AfxMessageBox("球员信息已成功写入数据库！");
}
void CImageDBView::OnButton2() 
{
	// TODO: Add your control notification handler code here
	CString sPno,sPname;
	CString strSQL;
	GetDlgItemText(IDC_EDIT1,sPno);
	GetDlgItemText(IDC_EDIT2,sPname);
	if (sPno.IsEmpty() && sPname.IsEmpty())
	{
		AfxMessageBox("您至少输入一个球员信息！");
		return;
	}
	
	if (sPname.IsEmpty())
		strSQL.Format("select * from Player where Pno='%s'",sPno);
	else if (sPno.IsEmpty())
		strSQL.Format("select * from Player where Pname='%s'",sPname);
	else
		strSQL.Format("select * from Player where Pno='%s' and Pname='%s'",sPno,sPname);
	_RecordsetPtr pRecordset;
	pRecordset.CreateInstance(__uuidof(Recordset));
	pRecordset->Open(_variant_t(strSQL),GetDocument()->m_pConnection.GetInterfacePtr(),adOpenDynamic,adLockOptimistic,adCmdText);
	if(pRecordset->BOF)
	{
		AfxMessageBox("您要找的球员不存在！");
		return;
	}
	
	_variant_t varPno=pRecordset->GetFields()->GetItem("Pno")->Value;
	_variant_t varPname=pRecordset->GetFields()->GetItem("Pname")->Value;
	CString a;
	SetDlgItemText(IDC_EDIT1,(LPCTSTR)(_bstr_t)varPno);
	SetDlgItemText(IDC_PNAME,(LPCTSTR)(_bstr_t)varPname);
	_StreamPtr pStm;
	pStm.CreateInstance(__uuidof(Stream));
	pStm->PutType(adTypeBinary);
	_variant_t varOptional(DISP_E_PARAMNOTFOUND,VT_ERROR);
	pStm->Open(varOptional,adModeUnknown,adOpenStreamUnspecified,_bstr_t(),_bstr_t());
	_variant_t varBLOB;
	varBLOB=pRecordset->GetFields()->GetItem(_variant_t("Photo"))->Value;
	pStm->Write(varBLOB);
	m_pStream=pStm;
	m_varBLOB=varBLOB;
	DrawPhotoFromDB();
	m_bDraw=2;
	CButton* pBtn=(CButton*)GetDlgItem(IDC_CHECK1);
	if (pBtn->GetCheck()==1)
	{
		CFileDialog FileDlg(FALSE,"*.jpg",NULL,Default(),"图片文件(*.jpg; *.bmp)|*.jpg; *.bmp||",NULL);
		FileDlg.DoModal();
		CString filename;
		filename=FileDlg.GetPathName();
		if (filename.IsEmpty())
			return;
		CFileFind findfile;
		int bExist=findfile.FindFile(filename);
		if (bExist)
		{
			AfxMessageBox("您要保存的文件已存在!");
			return;
		}
		Image_DB(FALSE,filename,pRecordset,"Photo");
	}	
	pRecordset->Close();
}
void CImageDBView::Image_DB(BOOL bImageToDB, LPCTSTR lpszFileName, _RecordsetPtr pRecordset, LPCTSTR lpszColumn)
{
	_StreamPtr pStm;
	pStm.CreateInstance(__uuidof(Stream));
	pStm->PutType(adTypeBinary);
	_variant_t varOptional(DISP_E_PARAMNOTFOUND,VT_ERROR);
	pStm->Open(varOptional,adModeUnknown,adOpenStreamUnspecified,_bstr_t(),_bstr_t());
	
	_variant_t varBLOB;
	if (bImageToDB)
	{
		pStm->LoadFromFile(_bstr_t(lpszFileName));
		varBLOB=pStm->Read(adReadAll);
		pRecordset->GetFields()->GetItem(_variant_t(lpszColumn))->Value=varBLOB;
		//或者用pRecordset->GetFields()->GetItem(_variant_t(lpszColumn))->AppendChunk(varBLOB);
		pRecordset->Update();
	} 
	else
	{
		varBLOB=pRecordset->GetFields()->GetItem(_variant_t(lpszColumn))->Value;
		//可以用GetChuck实现上面语句的功能。
		pStm->Write(varBLOB);
		pStm->SaveToFile(_bstr_t(lpszFileName),adSaveCreateOverWrite);
	}
}
void CImageDBView::OnDraw(CDC* pDC) 
{
	// TODO: Add your specialized code here and/or call the base class
	//DrawPhoto();
	if(m_bDraw==1)
		DrawPhotoFromFile(m_FileName);
	if(m_bDraw==2)
		DrawPhotoFromDB();
}
void CImageDBView::OnButton3() 
{
	// TODO: Add your control notification handler code here
	CFileDialog FileDlg(TRUE,"*.jpg",NULL,OFN_HIDEREADONLY,"图片文件(*.jpg; *.bmp)|*.jpg; *.bmp||",NULL);
	FileDlg.DoModal();
	CString filename;
	filename=FileDlg.GetPathName();
	if (filename.IsEmpty())
		return;	
	CFileFind findfile;
	int bExist=findfile.FindFile(filename);
	if (!bExist)
	{
		AfxMessageBox("您要打开的文件不存在！");
		return;
	}
	if (m_bImageOpen==FALSE)
		m_bImageOpen=TRUE;	
	m_FileName=filename;
	m_bDraw=1;
	DrawPhotoFromFile(m_FileName);
}
void CImageDBView::DrawPhotoFromFile(CString FileName)
{
	IStream *pStm; 
	CFile file; 
	if (file.Open(FileName,CFile::modeRead))
	{ 
		HGLOBAL hGlobal=GlobalAlloc(GMEM_MOVEABLE,file.GetLength()); 
		LPVOID pvData=NULL; 
		if (hGlobal!=NULL) 
		{ 
			if ((pvData = GlobalLock(hGlobal)) != NULL) 
			{ 
				file.ReadHuge(pvData,file.GetLength()); 
				GlobalUnlock(hGlobal); 
				CreateStreamOnHGlobal(pvData, TRUE, &pStm); 
			} 
		} 
	}  //使用void *pBuf=malloc(file.GetLength())代替hGlobal的方法不行，不知为何？？？
	
	IPicture* pPic;
	if(FAILED(OleLoadPicture(pStm,file.GetLength(),TRUE,IID_IPicture,(LPVOID*)&pPic))) 
		AfxMessageBox("从流中装载图像失败！");
	else
	{
		OLE_XSIZE_HIMETRIC pWidth;
		OLE_YSIZE_HIMETRIC pHeight;
		pPic->get_Width(&pWidth);
		pPic->get_Height(&pHeight);
		CDC *pDC=GetDC();
		CRect rt;
		GetDlgItem(IDC_PHOTO)->GetWindowRect(rt);
		ScreenToClient(rt);
		if(FAILED(pPic->Render(*pDC,rt.left+2,rt.top+2,rt.Width()-5,rt.Height()-5,0,pHeight,pWidth,-pHeight,NULL))) 
			AfxMessageBox( "图像渲染失败！"); 
		
		//////////////////////////////////////////////////////////////////////////
		/*可以根据图片大小显示
		double fx,fy;
		fx = (double) pDC->GetDeviceCaps(HORZRES)*(double)pWidth/			
			((double)pDC->GetDeviceCaps(HORZSIZE)*300.0); 		//改变数值可以改变图片显示的比例
		fy = (double)pDC->GetDeviceCaps(VERTRES)*(double)pHeight/			
			((double)pDC->GetDeviceCaps(VERTSIZE)*300.0); 	
		pPic->Render(*pDC,400,0,(LONG)fx,(LONG)fy,0,pHeight,pWidth,-pHeight,NULL);
		*//////////////////////////////////////////////////////////////////////////
	}
}
void CImageDBView::DrawPhotoFromDB()
{
	//将_StreamPtr *pstream 转为IStream *ps，因为OleLoadPicture需要的流是IStream流，_StreamPtr流不行。
	//LPVOID pvData = NULL; 
	IStream *ps; 
	void* pBuf=malloc(size_t(m_pStream->GetSize()));
	SafeArrayAccessData(m_varBLOB.parray,(void **) &pBuf);
	SafeArrayUnaccessData(m_varBLOB.parray);
	CreateStreamOnHGlobal(pBuf, TRUE, &ps);	
	//不能释放内存pBuf，因为ps只是个流，不具备pBuf的全部信息，离开pBuf，就不行了。
	
	IPicture *pPic; 	
	if(SUCCEEDED(OleLoadPicture(ps,m_pStream->GetSize() ,TRUE,IID_IPicture,(LPVOID*)&pPic))) 
	{
		OLE_XSIZE_HIMETRIC hmWidth; 
		OLE_YSIZE_HIMETRIC hmHeight; 
		pPic->get_Width(&hmWidth); 
		pPic->get_Height(&hmHeight); 
		CRect rt;
		GetDlgItem(IDC_PHOTO)->GetWindowRect(rt);
		ScreenToClient(rt);
		CDC *pDC=GetDC();
		if(FAILED(pPic->Render(*pDC,rt.left+2,rt.top+2,rt.Width()-5,rt.Height()-5,0,hmHeight,hmWidth,-hmHeight,NULL))) 
			AfxMessageBox( "图像渲染失败！"); 
	}
}

						