繪制連續的直線

1.首先建立MFC單文檔工程lessonMyLine3.

2.在其類視圖内選擇lessonMyLine3View類，在其中添加消息事件“onLButtonUp”、OnLButtonDown、OnMouseMove。

3.完成上述消息内的代碼。

// lessonMyLine3View.cpp : implementation of the ClessonMyLine3View class
//

#include "stdafx.h"
// SHARED_HANDLERS can be defined in an ATL project implementing preview, thumbnail
// and search filter handlers and allows sharing of document code with that project.
#ifndef SHARED_HANDLERS
#include "lessonMyLine3.h"
#endif

#include "lessonMyLine3Doc.h"
#include "lessonMyLine3View.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif


// ClessonMyLine3View

IMPLEMENT_DYNCREATE(ClessonMyLine3View, CView)

BEGIN_MESSAGE_MAP(ClessonMyLine3View, CView)
  // Standard printing commands
  ON_COMMAND(ID_FILE_PRINT, &CView::OnFilePrint)
  ON_COMMAND(ID_FILE_PRINT_DIRECT, &CView::OnFilePrint)
  ON_COMMAND(ID_FILE_PRINT_PREVIEW, &ClessonMyLine3View::OnFilePrintPreview)
  ON_WM_CONTEXTMENU()
  ON_WM_RBUTTONUP()
  ON_WM_LBUTTONUP()
  ON_WM_LBUTTONDOWN()
  ON_WM_MOUSEMOVE()
END_MESSAGE_MAP()

// ClessonMyLine3View construction/destruction

ClessonMyLine3View::ClessonMyLine3View()
  : m_MouseDown(false)
  , m_point(0)
{
  // TODO: add construction code here

}

ClessonMyLine3View::~ClessonMyLine3View()
{
}

BOOL ClessonMyLine3View::PreCreateWindow(CREATESTRUCT& cs)
{
  // TODO: Modify the Window class or styles here by modifying
  //  the CREATESTRUCT cs

  return CView::PreCreateWindow(cs);
}

// ClessonMyLine3View drawing

void ClessonMyLine3View::OnDraw(CDC* /*pDC*/)
{
  ClessonMyLine3Doc* pDoc = GetDocument();
  ASSERT_VALID(pDoc);
  if (!pDoc)
    return;

  // TODO: add draw code for native data here
}


// ClessonMyLine3View printing


void ClessonMyLine3View::OnFilePrintPreview()
{
#ifndef SHARED_HANDLERS
  AFXPrintPreview(this);
#endif
}

BOOL ClessonMyLine3View::OnPreparePrinting(CPrintInfo* pInfo)
{
  // default preparation
  return DoPreparePrinting(pInfo);
}

void ClessonMyLine3View::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
  // TODO: add extra initialization before printing
}

void ClessonMyLine3View::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
  // TODO: add cleanup after printing
}

void ClessonMyLine3View::OnRButtonUp(UINT /* nFlags */, CPoint point)
{
  ClientToScreen(&point);
  OnContextMenu(this, point);
}

void ClessonMyLine3View::OnContextMenu(CWnd* /* pWnd */, CPoint point)
{
#ifndef SHARED_HANDLERS
  theApp.GetContextMenuManager()->ShowPopupMenu(IDR_POPUP_EDIT, point.x, point.y, this, TRUE);
#endif
}


// ClessonMyLine3View diagnostics

#ifdef _DEBUG
void ClessonMyLine3View::AssertValid() const
{
  CView::AssertValid();
}

void ClessonMyLine3View::Dump(CDumpContext& dc) const
{
  CView::Dump(dc);
}

ClessonMyLine3Doc* ClessonMyLine3View::GetDocument() const // non-debug version is inline
{
  ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(ClessonMyLine3Doc)));
  return (ClessonMyLine3Doc*)m_pDocument;
}
#endif //_DEBUG


// ClessonMyLine3View message handlers


void ClessonMyLine3View::OnLButtonUp(UINT nFlags, CPoint point)
{
  // TODO: Add your message handler code here and/or call default
  m_MouseDown=false;
  CView::OnLButtonUp(nFlags, point);
}


void ClessonMyLine3View::OnLButtonDown(UINT nFlags, CPoint point)
{
  // TODO: Add your message handler code here and/or call default
  m_point=point;
  m_MouseDown=true;
  CView::OnLButtonDown(nFlags, point);
}


void ClessonMyLine3View::OnMouseMove(UINT nFlags, CPoint point)
{
  // TODO: Add your message handler code here and/or call default
  CClientDC ccdc(this);
  if(m_MouseDown)
  {
    ccdc.MoveTo(m_point);
    ccdc.LineTo(point);
    m_point=point;
  }
  CView::OnMouseMove(nFlags, point);
}