MFC对话框处理滚动条

MFC对话框处理滚动条
flyfish
原理
nMin
Specifies the minimum scrolling position.
滚动条范围最小值
nMax
Specifies the maximum scrolling position.
滚动条范围最大值
nPage
Specifies the page size. A scroll bar uses this value to determine the appropriate size of the
proportional scroll box.
页尺寸，用来确定比例滚动条的大小
nPos
Specifies the position of the scroll box.
滚动条的位置
以垂直滚动条为例，假设一个窗口高度1080像素，而显示器或者用户看到的只有768像素，那么就可以设置
nMax=1080，nPage=768.
头文件

//成员变量

//在资源视图中看到的对话框的大小
CRect   m_rectOriginal;

// 鼠标拖拽
BOOL    m_bDragging;
CPoint  m_ptDragPoint;

// 滚动条实际位置
int m_nScrollPos;

// 对话框实际高度
int m_nCurrentHeight;

//消息函数
afx_msg void OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar);
afx_msg void OnSize(UINT nType, int cx, int cy);
afx_msg BOOL OnMouseWheel(UINT nFlags, short zDelta, CPoint pt);
afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
afx_msg void OnMouseMove(UINT nFlags, CPoint point);
afx_msg void OnKillFocus(CWnd* pNewWnd);

//重写函数
virtual BOOL OnInitDialog();

//增加函数
void EndDrag();

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实现文件

//消息映射
ON_WM_VSCROLL()
ON_WM_SIZE()
ON_WM_MOUSEWHEEL()
ON_WM_LBUTTONDOWN()
ON_WM_LBUTTONUP()
ON_WM_MOUSEMOVE()
ON_WM_KILLFOCUS()

//实现函数
void CDlgX::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO:  在此添加消息处理程序代码和/或调用默认值
int nDelta;
int nMaxPos = m_rectOriginal.Height() - m_nCurrentHeight;

switch (nSBCode)
{
case SB_LINEDOWN:
if (m_nScrollPos >= nMaxPos)
return;

nDelta = min(max(nMaxPos / 20, 5), nMaxPos - m_nScrollPos);
break;

case SB_LINEUP:
if (m_nScrollPos <= 0)
return;
nDelta = -min(max(nMaxPos / 20, 5), m_nScrollPos);
break;
case SB_PAGEDOWN:
if (m_nScrollPos >= nMaxPos)
return;
nDelta = min(max(nMaxPos / 10, 5), nMaxPos - m_nScrollPos);
break;
case SB_THUMBTRACK:
case SB_THUMBPOSITION:
nDelta = (int)nPos - m_nScrollPos;
break;

case SB_PAGEUP:
if (m_nScrollPos <= 0)
return;
nDelta = -min(max(nMaxPos / 10, 5), m_nScrollPos);
break;

default:
return;
}
m_nScrollPos += nDelta;
SetScrollPos(SB_VERT, m_nScrollPos, TRUE);
ScrollWindow(0, -nDelta);
CDialogEx::OnVScroll(nSBCode, nPos, pScrollBar);
}

void CDlgX::OnSize(UINT nType, int cx, int cy)
{
CDialogEx::OnSize(nType, cx, cy);

// TODO:  在此处添加消息处理程序代码
m_nCurrentHeight = cy;

SCROLLINFO si;
si.cbSize = sizeof(SCROLLINFO);
si.fMask = SIF_ALL;
si.nMin = 0;
si.nMax = m_rectOriginal.Height();
si.nPage = cy;
si.nPos = 0;
SetScrollInfo(SB_VERT, &si, TRUE);
}

BOOL CDlgX::OnMouseWheel(UINT nFlags, short zDelta, CPoint pt)
{
// TODO:  在此添加消息处理程序代码和/或调用默认值
int nMaxPos = m_rectOriginal.Height() - m_nCurrentHeight;

if (zDelta < 0)
{
if (m_nScrollPos < nMaxPos)
{
zDelta = min(max(nMaxPos / 20, 5), nMaxPos - m_nScrollPos);

m_nScrollPos += zDelta;
SetScrollPos(SB_VERT, m_nScrollPos, TRUE);
ScrollWindow(0, -zDelta);
}
}
else
{
if (m_nScrollPos > 0)
{
zDelta = -min(max(nMaxPos / 20, 5), m_nScrollPos);

m_nScrollPos += zDelta;
SetScrollPos(SB_VERT, m_nScrollPos, TRUE);
ScrollWindow(0, -zDelta);
}
}
return CDialogEx::OnMouseWheel(nFlags, zDelta, pt);
}

void CDlgX::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
m_bDragging = TRUE;
SetCapture();

m_ptDragPoint = point;
CDialogEx::OnLButtonDown(nFlags, point);
}

void CDlgX::OnLButtonUp(UINT nFlags, CPoint point)
{
// TODO:  在此添加消息处理程序代码和/或调用默认值
EndDrag();
CDialogEx::OnLButtonUp(nFlags, point);
}

void CDlgX::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
if (m_bDragging)
{
int nDelta = m_ptDragPoint.y - point.y;
m_ptDragPoint = point;

int nNewPos = m_nScrollPos + nDelta;

if (nNewPos<0)
nNewPos = 0;
else if (nNewPos>m_rectOriginal.Height() - m_nCurrentHeight)
nNewPos = m_rectOriginal.Height() - m_nCurrentHeight;

nDelta = nNewPos - m_nScrollPos;
m_nScrollPos = nNewPos;

SetScrollPos(SB_VERT, m_nScrollPos, TRUE);
ScrollWindow(0, -nDelta);
}
CDialogEx::OnMouseMove(nFlags, point);
}

void CDlgX::OnKillFocus(CWnd* pNewWnd)
{
CDialogEx::OnKillFocus(pNewWnd);

// TODO:  在此处添加消息处理程序代码
EndDrag();
}

BOOL CDlgX::OnInitDialog()
{
CDialogEx::OnInitDialog();

// TODO:  在此添加额外的初始化

//存储对话框初始大小
GetWindowRect(m_rectOriginal);

//初始滚动条位置
m_nScrollPos = 0;

return TRUE;  // return TRUE unless you set the focus to a control
// 异常:  OCX 属性页应返回 FALSE
}
void CDlgX::EndDrag()
{
m_bDragging = FALSE;
ReleaseCapture();
//SetCursor(m_hCursor1);
}

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**

另一种方法 使用CScrollBar类的方法

**
对话框中添加一个垂直滚动条 vertical scroll bar
为其绑定一个控件变量 m_vScroll
增加消息WM_MOUSEWHEEL ,WM_VSCROLL
头文件
增加
CScrollBar m_vScroll;
afx_msg void OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar);
afx_msg BOOL OnMouseWheel(UINT nFlags, short zDelta, CPoint pt);
int m_nScrollUnitHeight = 20;//一条记录的高度
int m_nUnitCount = 10;//记录总数

CRect m_rectScroll;//滚动条的rect
int m_nScrollPos;//滚动条位置

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实现文件
绑定变量的时候向导会自动增加数据交换
void CMFCDlg::DoDataExchange(CDataExchange* pDX)
{
CDialogEx::DoDataExchange(pDX);
DDX_Control(pDX, IDC_SCROLLBAR1, m_vScroll);
}
增加消息的时候 向导会自动增加消息映射的代码
BEGIN_MESSAGE_MAP(CMFCDlg, CDialogEx)
ON_WM_VSCROLL()
ON_WM_MOUSEWHEEL()
END_MESSAGE_MAP()
对话框初始化增加

CRect rect;
GetClientRect(rect);
SCROLLINFO si;
si.cbSize = sizeof(SCROLLINFO);;
si.nMin = 0;
si.nMax = m_nScrollUnitHeight*m_nUnitCount;
si.nPage = m_nScrollUnitHeight;
si.fMask = SIF_POS | SIF_RANGE | SIF_PAGE;

m_vScroll.SetScrollInfo(&si, TRUE);

m_vScroll.GetWindowRect(m_rectScroll);//滚动条所在的位置
ScreenToClient(m_rectScroll);

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其他实现函数

void CMFCDlg::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
// TODO:  在此添加消息处理程序代码和/或调用默认值
SCROLLINFO si;
si.cbSize = sizeof(si);
m_vScroll.GetScrollInfo(&si, SIF_POS | SIF_PAGE | SIF_RANGE);
m_nScrollPos = si.nPos;
switch (nSBCode)
{
case SB_LINEDOWN:  m_nScrollPos += 10;
if (m_nScrollPos > (si.nMax - si.nMin - si.nPage))
{
m_nScrollPos = si.nMax - si.nMin - si.nPage;

}
break;

case SB_LINEUP:    m_nScrollPos -= 10;
if (m_nScrollPos < si.nMin)
{
m_nScrollPos = 0;
}
break;
case SB_PAGEDOWN:  m_nScrollPos += si.nPage;
if (m_nScrollPos > (si.nMax - si.nMin - si.nPage))
{
m_nScrollPos = si.nMax - si.nMin - si.nPage;

}
break;
case SB_PAGEUP:  m_nScrollPos -= si.nPage;
if (m_nScrollPos < si.nMin)
{
m_nScrollPos = 0;
}
break;
case  SB_THUMBTRACK: m_nScrollPos = nPos; break;

}

ScrollWindow(0, -(m_nScrollPos - si.nPos), NULL, NULL);
m_vScroll.MoveWindow(m_rectScroll, TRUE);

si.fMask = SIF_POS;
si.nPos = m_nScrollPos;
m_vScroll.SetScrollInfo(&si, TRUE);
CDialogEx::OnVScroll(nSBCode, nPos, pScrollBar);
}

BOOL CMFCDlg::OnMouseWheel(UINT nFlags, short zDelta, CPoint pt)
{
// TODO:  在此添加消息处理程序代码和/或调用默认值
if (zDelta == -120)
{

m_nScrollPos += 10;
OnVScroll(SB_PAGEDOWN, m_nScrollPos, &m_vScroll);
}
else if (zDelta == 120)
{
m_nScrollPos -= 10;
OnVScroll(SB_PAGEUP, m_nScrollPos, &m_vScroll);

}

m_vScroll.MoveWindow(m_rectScroll, TRUE);
return CDialogEx::OnMouseWheel(nFlags, zDelta, pt);
}