rowview.h

VC++技术内幕(第四版)的实例

// rowview.h : interface of the CRowView class
//
// This class implements the behavior of a scrolling view that presents
// multiple rows of fixed-height data.  A row view is similar to an
// owner-draw listbox in its visual behavior; but unlike listboxes,
// a row view has all of the benefits of a view (as well as scroll view),
// including perhaps most importantly printing and print preview.
/////////////////////////////////////////////////////////////////////////////

class CRowView : public CScrollView  // abstract base class
{
DECLARE_DYNAMIC(CRowView)
protected:
// Construction/destruction
	CRowView();
	virtual ~CRowView();
// Attributes
protected:
	int m_nRowWidth;			// width of row in logical units
	int	m_nRowHeight; 			// height of row in logical units
	int	m_nCharWidth; 			// avg char width in logical units
	int m_nPrevSelectedRow;		// index of the most recently selected row
	int m_nPrevRowCount;		// most recent row count, before update
	int m_nRowsPerPrintedPage;	// how many rows fit on a printed page

// Operations-Attributes
protected:
	virtual void UpdateRow(int nInvalidRow); // called by derived class OnUpdate
	virtual void CalculateRowMetrics(CDC* pDC)
		{ GetRowWidthHeight(pDC, m_nRowWidth, m_nRowHeight, m_nCharWidth); }
	virtual void UpdateScrollSizes();
	virtual CRect RowToWndRect(CDC* pDC, int nRow);
	virtual int RowToYPos(int nRow);
	virtual void RectLPtoRowRange(const CRect& rectLP, 
			int& nFirstRow,	int& nLastRow, BOOL bIncludePartiallyShownRows);
	virtual int LastViewableRow();

// Overridables
protected:
	virtual void GetRowWidthHeight(CDC* pDC, int& nRowWidth, 
		int& nRowHeight, int& nCharWidth) = 0;
	virtual int GetActiveRow() = 0;
	virtual int GetRowCount() = 0;
	virtual void OnDrawRow(CDC* pDC, int nRow, int y, BOOL bSelected) = 0;
	virtual void ChangeSelectionNextRow(BOOL bNext) = 0;
	virtual void ChangeSelectionToRow(int nRow) = 0;

// Implementation
protected:
	// standard overrides of MFC classes
	virtual void OnInitialUpdate();
	virtual void OnDraw(CDC* pDC);  // overridden to draw this view
    virtual void OnPrepareDC(CDC* pDC, CPrintInfo* pInfo = NULL);
	virtual BOOL OnPreparePrinting(CPrintInfo* pInfo);
	virtual void OnBeginPrinting(CDC* pDC, CPrintInfo* pInfo);
	virtual void OnPrint(CDC* pDC, CPrintInfo* pInfo);

// Generated message map functions
protected:
	//{{AFX_MSG(CRowView)
	afx_msg void OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags);
	afx_msg void OnSize(UINT nType, int cx, int cy);
	afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
	//}}AFX_MSG
	DECLARE_MESSAGE_MAP()
};