如何获取鼠标点击所在点的坐标？

[chenthree723]

具体情况是我要利用ONLBUTTONDOWN和ONMOUSEMOVE画一条折线，并计算这条折线的函数表达式。所以在点击鼠标的时候，需要记录每一个点击左键时候的点的坐标，放进一个动态数组里。下面是我的代码，哪个地方出错了？

void CWaveTestView::OnMouseMove(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default

// CString sMousePos;
// sMousePos.Format("x=%d,y=%d",point.x,point.y);
// GetParent()->GetDescendantWindow(AFX_IDW_STATUS_BAR)->SetWindowText(sMousePos);

if (m_OnDrawLine == TRUE)
{
int nPointCount = 0;

CPoint *pDrawPoint = new CPoint[];

if(nFlags==MK_LBUTTON) //按下左键
{
CPen pen,cpen;
pen.CreatePen(PS_SOLID,4,RGB(0,0,0));
cpen.CreatePen(PS_SOLID,2,RGB(0,0,255));

m_PtOld = point;//鼠标当前位置相对下一次移动的位置是“旧位置”

CClientDC dc(this);
dc.SetROP2(R2_NOT);
dc.SelectObject(&pen);
dc.MoveTo(m_PtStart);
dc.LineTo(m_PtOld);
dc.MoveTo(m_PtStart);
dc.LineTo(point);

nPointCount++;
}

for (int i=0;i<nPointCount;i++)
{
pDrawPoint[i] = point;
}

}



CView::OnMouseMove(nFlags, point);
}

另外，上面有段被注释掉的代码，是想显示鼠标当前位置的坐标，但是在运行的时候，会提示“UNHANDLED EXCEPTION IN xxxx.exe access violation”,请帮忙一并解决，我新人，分不多。谢谢！

[qlizhang]

void CTrailMousePosDlg::OnMouseMove(UINT nFlags, CPoint point)
{
//获得鼠标当前位置
m_strX.Format("%d",point.x);
m_strY.Format("%d",point.y);
UpdateData(FALSE);

CDialog::OnMouseMove(nFlags, point);
}

[lgstudyvc]

m_PtStart值呢？

在说了，你跟进去看看啊，值是多少

[qlizhang]

在点击事件中记录坐标并画线。

[BombZhang]

下面两个都应该是类的成员变量，否则没办法保存每次点击的坐标
int nPointCount;
CPoint *pDrawPoint;

而且不能用CPoint *pDrawPoint;
用个CList比较合适,每点击一次在list中增加一个point对象
CList<CPoint,CPoint> m_Points;

[schlafenhamster]

CPoint *pDrawPoint = new CPoint[];// 多少？
知道：nPointCount 后 再new：
CPoint *pDrawPoint = new CPoint[nPointCount];

[看不见的裂痕]

CPoint *pDrawPoint = new CPoint[];

这句话问题很大。
不确定大小的话，
1.可以先申请个很大的空间
2.用容器Vector之类的

[zgl7903]

稍微整理一下

class CWaveTestDoc : public CDocument
{
public:
  CArray< POINT, const POINT& >PointArray;
  POINT PointLastActive, PointLast;
  
 ……

//WM_PAINT中绘制所有点
void CWaveTestView::OnDraw(CDC* pDC)
{
  CWaveTestDoc* pDoc = GetDocument();
  ASSERT_VALID(pDoc);
  if (!pDoc)
    return;

  //添加绘制背景代码
  CRect rcClient;
  GetClientRect(&rcClient);
  pDC->FillSolidRect(rcClient, RGB(255,255,255));

  // TODO: 在此处为本机数据添加绘制代码
  if(pDoc->PointArray.GetSize() > 1)
  {
    CPen LinePen(PS_SOLID, 1, RGB(255,0,0));
    CPen *pOldPen = pDC->SelectObject(&LinePen);
    pDC->MoveTo(pDoc->PointArray[0]);

    for(INT_PTR iPos=1; iPos<pDoc->PointArray.GetSize(); iPos++)
    {
      pDC->LineTo(pDoc->PointArray[iPos]);
    }
    pDC->SelectObject(pOldPen);
  }
}

//左键点下加入新点
void CWaveTestView::OnLButtonDown(UINT nFlags, CPoint point)
{
  // TODO: 在此添加消息处理程序代码和/或调用默认值  
  CWaveTestDoc* pDoc = GetDocument();
  pDoc->PointArray.Add(point);
  pDoc->PointLast = pDoc->PointLastActive = point;
  InvalidateRect(NULL, TRUE);

  CView::OnMButtonDown(nFlags, point);
}

//移动鼠标时绘制从最后一点到当前鼠标点的线
void CWaveTestView::OnMouseMove(UINT nFlags, CPoint point)
{
  // TODO: 在此添加消息处理程序代码和/或调用默认值
  CWaveTestDoc* pDoc = GetDocument();
  if(pDoc->PointArray.GetSize())
  {
    if(point != pDoc->PointLast)
    {
      CClientDC dc(this);
      CDC *pDC = &dc;

      CPen LinePen(PS_SOLID, 5, RGB(255,0,0));
      CPen *pOldPen = pDC->SelectObject(&LinePen);

      int rop2 = pDC->SetROP2(R2_XORPEN);

      pDC->MoveTo(pDoc->PointLastActive);
      pDC->LineTo(pDoc->PointLast);

      pDC->MoveTo(pDoc->PointLastActive);
      pDC->LineTo(point);

      pDoc->PointLast = point;

      pDC->SetROP2(rop2);
      pDC->SelectObject(pOldPen);
      
      //InvalidateRect(NULL);
    }
  }

  CView::OnMouseMove(nFlags, point);
}

//右键双击取消所有点
void CWaveTestView::OnRButtonDblClk(UINT nFlags, CPoint point)
{
  // TODO: 在此添加消息处理程序代码和/或调用默认值
  CWaveTestDoc* pDoc = GetDocument();
  if(pDoc->PointArray.GetSize())
  {
    pDoc->PointArray.RemoveAll();
    pDoc->PointLastActive = pDoc->PointLastActive = CPoint(-1, -1);
    InvalidateRect(NULL);
  }
  CView::OnRButtonDblClk(nFlags, point);
}