The CAdjustSlider that I overwrite from CSliderCtrl can not send WM_HSCROLL message when i drag the

EDN Admin · Oct 16, 2012

I writed a class named CADjustSlider which inherited from CSliderCtrl, but when i drag the slider of the ctrl with mouse, its parent windows WM_HSCROLL message handler does not response.

thank you very much for reading and giving some advices to me.
the header file:
#if !defined(AFX_MYSLIDER_H__E434F151_26B7_45C1_89F0_2E59B3D642E2__INCLUDED_) 
#define AFX_MYSLIDER_H__E434F151_26B7_45C1_89F0_2E59B3D642E2__INCLUDED_
#if _MSC_VER > 1000 
#pragma once 
#endif // _MSC_VER > 1000 
 
// CAdjustSlider window
class CAdjustSlider : public CSliderCtrl 
{ 
// Construction 
public: 
CAdjustSlider();
// Attributes 
public:
// Operations 
public:
// Overrides 
// ClassWizard generated virtual function overrides 
//{{AFX_VIRTUAL(CAdjustSlider) 
protected: 
virtual void PreSubclassWindow(); 
//}}AFX_VIRTUAL
// Implementation 
public: 
virtual ~CAdjustSlider();
// Generated message map functions 
protected: 
//{{AFX_MSG(CAdjustSlider) 
afx_msg void OnPaint(); 
afx_msg BOOL OnEraseBkgnd(CDC* pDC); 
afx_msg void OnLButtonUp(UINT nFlags, CPoint point); 
afx_msg void OnLButtonDown(UINT nFlags, CPoint point); 
afx_msg void OnMouseMove(UINT nFlags, CPoint point); 
//}}AFX_MSG 
private: 
bool m_flagLBtnDownInThumb; // true:鼠标左键在thumb区域被按下； 
CRect m_rtClient; // slider控件的客户区域； 
CRect m_rtChannel; // channel的矩形区域大小； 
CRect m_rtThumb; // thumb的矩形区域大小； 
CRect m_rtCurPosThumb; // thumb当前的区域； 
CPoint m_ptInChannel; 
CBitmap m_ThumbMask; 
CBitmap m_ThumbBmp; 
COLORREF m_BackColor; // thumb滑块区域的背景色，一般和控件所在对话框的颜色相同，重绘时，会用到该颜色； 
public: 
void SetBkcolor(COLORREF rgb); // 设置m_BackColor; 
void SetPos(int nPos); 
DECLARE_MESSAGE_MAP() 
afx_msg void OnTimer(UINT_PTR nIDEvent); 
};
/////////////////////////////////////////////////////////////////////////////
//{{AFX_INSERT_LOCATION}} 
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.
#endif // !defined(AFX_MYSLIDER_H__E434F151_26B7_45C1_89F0_2E59B3D642E2__INCLUDED_)
the source file:

#include "stdafx.h" 
#include "AdjustSlider.h"
 
#ifdef _DEBUG 
#define new DEBUG_NEW 
#undef THIS_FILE 
static char THIS_FILE[] = __FILE__; 
#endif
///////////////////////////////////////////////////////////////////////////// 
// CAdjustSlider
CAdjustSlider::CAdjustSlider() 
{ 
m_flagLBtnDownInThumb = false; 
m_ThumbMask.LoadBitmap(IDB_BITMAP_THUMBMASK); 
m_ThumbBmp.LoadBitmap(IDB_BITMAP_THUMB); 
m_BackColor = RGB(211, 211, 211); 
}
CAdjustSlider::~CAdjustSlider() 
{ 
if (m_ThumbBmp.m_hObject) 
{ 
m_ThumbBmp.DeleteObject(); 
} 
if (m_ThumbMask.m_hObject) 
{ 
m_ThumbMask.DeleteObject(); 
} 
}
 
BEGIN_MESSAGE_MAP(CAdjustSlider, CSliderCtrl) 
//{{AFX_MSG_MAP(CAdjustSlider) 
ON_WM_PAINT() 
ON_WM_ERASEBKGND() 
ON_WM_LBUTTONUP() 
ON_WM_LBUTTONDOWN() 
ON_WM_MOUSEMOVE() 
//}}AFX_MSG_MAP 
ON_WM_TIMER() 
END_MESSAGE_MAP()
///////////////////////////////////////////////////////////////////////////// 
// CAdjustSlider message handlers
void CAdjustSlider::OnPaint() 
{ 
CPaintDC dc(this); // device context for painting 
 
// TODO: Add your message handler code here 
 
dc.FillRect(&m_rtClient, &CBrush(m_BackColor)); 
dc.FillRect(&m_rtChannel, &CBrush(RGB(255, 255, 255))); 
 
 
 
CDC *pDC, pMemDC, pMaskDC; 
pDC = GetDC(); 
pMemDC.CreateCompatibleDC(pDC); 
pMaskDC.CreateCompatibleDC(pDC);
pMemDC.SelectObject(&m_ThumbBmp); 
pMaskDC.SelectObject(&m_ThumbMask);
pDC->BitBlt(m_rtCurPosThumb.left, m_rtCurPosThumb.top, m_rtThumb.Width(), m_rtThumb.Height(), &pMaskDC, 0, 0, MERGEPAINT); 
pDC->BitBlt(m_rtCurPosThumb.left, m_rtCurPosThumb.top, m_rtThumb.Width(), m_rtThumb.Height(), &pMemDC, 0, 0, SRCAND);
ReleaseDC(pDC);
// Do not call CSliderCtrl::OnPaint() for painting messages 
}
BOOL CAdjustSlider::OnEraseBkgnd(CDC* pDC) 
{ 
// TODO: Add your message handler code here and/or call default 
 
return true; 
}
void CAdjustSlider::OnLButtonUp(UINT nFlags, CPoint point) 
{ 
// TODO: Add your message handler code here and/or call default 
if (m_flagLBtnDownInThumb) 
{ 
m_flagLBtnDownInThumb = false; 
ReleaseCapture(); 
} 
 
CSliderCtrl::OnLButtonUp(nFlags, point); 
}
void CAdjustSlider::OnLButtonDown(UINT nFlags, CPoint point) 
{ 
// TODO: Add your message handler code here and/or call default 
if (m_rtCurPosThumb.PtInRect(point)) 
{ 
m_flagLBtnDownInThumb = true; 
SetCapture(); 
} 
else if (m_rtChannel.PtInRect(point)) 
{ 
int nMax = 0; 
int nMin = 0; 
GetRange(nMin,nMax); 
int nPos = (nMax - nMin)*(point.x - m_rtClient.left - m_rtChannel.left)/(m_rtChannel.right - m_rtChannel.left);
 
nPos += nMin; 
SetPos(nPos); 
 
Invalidate(); 
CSliderCtrl::OnLButtonDown(nFlags, point); 
} 
}
void CAdjustSlider::OnMouseMove(UINT nFlags, CPoint point) 
{ 
// TODO: Add your message handler code here and/or call default 
if (MK_LBUTTON == nFlags) 
{ 
if (m_flagLBtnDownInThumb) 
{ 
if (point.x > m_rtChannel.right) 
{ 
point.x = m_rtChannel.right; 
} 
if (point.x < m_rtChannel.left) 
{ 
point.x = m_rtChannel.left; 
}
int nMax = 0; 
int nMin = 0; 
GetRange(nMin,nMax); 
int nPos = (nMax - nMin)*(point.x - m_rtClient.left - m_rtChannel.left)/(m_rtChannel.right - m_rtChannel.left);
 
nPos += nMin; 
SetPos(nPos); 
Invalidate(); 
//::SendMessage(GetParent()->GetSafeHwnd(), WM_HSCROLL, TB_THUMBTRACK, 0); 
} 
}
CSliderCtrl::OnMouseMove(nFlags, point); 
}

void CAdjustSlider:

reSubclassWindow() 
{ 
// TODO: Add your specialized code here and/or call the base class 
GetClientRect(&m_rtClient); 
GetChannelRect(&m_rtChannel); 
GetThumbRect(&m_rtThumb);
m_rtChannel.bottom = m_rtChannel.top + 5; 
m_rtThumb.top = m_rtChannel.bottom + 1; 
m_rtThumb.bottom = m_rtThumb.top + 11; 
m_rtThumb.left = m_rtChannel.left - 5; 
m_rtThumb.right = m_rtThumb.left + 11;
m_rtCurPosThumb = m_rtThumb;
m_ptInChannel.x = m_rtCurPosThumb.left + m_rtCurPosThumb.Width() / 2; 
m_ptInChannel .y = m_rtChannel.top + m_rtChannel.Height() / 2;
 
CSliderCtrl:

reSubclassWindow(); 
}
void CAdjustSlider::SetBkcolor(COLORREF rgb) 
{ 
m_BackColor = rgb; 
}
void CAdjustSlider::SetPos(int nPos) 
{ 
int min, max; 
GetRange(min, max); 
 
if (nPos < min) 
{ 
nPos = min; 
} 
if (nPos > max) 
{ 
nPos = max; 
} 
 
int temp = (m_rtChannel.right - m_rtChannel.left) * (nPos - min) / (max - min); 
m_rtCurPosThumb.left = m_rtChannel.left + temp - m_rtThumb.Width() / 2; 
if (m_rtCurPosThumb.left < m_rtChannel.left - m_rtThumb.Width() / 2) 
{ 
m_rtCurPosThumb.left = m_rtChannel.left - m_rtThumb.Width() / 2; 
} 
if (m_rtCurPosThumb.left > m_rtChannel.right - m_rtThumb.Width() / 2) 
{ 
m_rtCurPosThumb.left = m_rtChannel.right - m_rtThumb.Width() / 2; 
} 
m_rtCurPosThumb.right = m_rtCurPosThumb.left + m_rtThumb.Width(); 
m_rtCurPosThumb.bottom = m_rtCurPosThumb.top + m_rtThumb.Height(); 
m_rtCurPosThumb.top = m_rtChannel.bottom + 1;
CSliderCtrl::SetPos(nPos); 
}
void CAdjustSlider::OnTimer(UINT_PTR nIDEvent) 
{ 
// TODO: Add your message handler code here and/or call default 
if (nIDEvent == 1) 
{ 
SendMessage(WM_LBUTTONDOWN); 
//SetTimer(1, 100, NULL); 
} 
CSliderCtrl::OnTimer(nIDEvent); 
}

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The CAdjustSlider that I overwrite from CSliderCtrl can not send WM_HSCROLL message when i drag the

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