CSliderCtrl自绘开发

效果：

鼠标热点（黄色）：

代码下载：点击打开链接

1、首先说一下，当我们拖动滑块控件时，滑块控件的响应函数：1）当滑块是横向滑块时，为滑块父窗口的WM_HSCROLL消息添加响应函数；2）当滑块是竖向滑块时，为滑块父窗口的WM_VSCROLL消息添加响应函数。

2、自绘原理：创建一个CSliderCtrl的派生类：CMySliderCtrl；建立一个派生类类型的控件变量：CMySliderCtrl m_Slider;。

3、自绘操作是在派生类中进行，涉及到的主要函数有：

public:
	BOOL m_bTrack;
	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 OnPaint();
	afx_msg BOOL OnEraseBkgnd(CDC* pDC);

实现如下：

// MySliderCtrl.cpp : 实现文件
//

#include "stdafx.h"
#include "CSliderCtrl自绘.h"
#include "MySliderCtrl.h"


// CMySliderCtrl

IMPLEMENT_DYNAMIC(CMySliderCtrl, CSliderCtrl)

CMySliderCtrl::CMySliderCtrl()
{
	m_bTrack = FALSE;
}

CMySliderCtrl::~CMySliderCtrl()
{
}

BEGIN_MESSAGE_MAP(CMySliderCtrl, CSliderCtrl)
	ON_WM_LBUTTONDOWN()
	ON_WM_LBUTTONUP()
	ON_WM_MOUSEMOVE()
	ON_WM_PAINT()
	ON_WM_ERASEBKGND()
	ON_WM_HSCROLL()
END_MESSAGE_MAP()

// CMySliderCtrl 消息处理程序

void CMySliderCtrl::OnLButtonDown(UINT nFlags, CPoint point)
{
	CRect rcTotal,rcThumb,rcEdge;
	GetClientRect(&rcTotal);
	GetThumbRect(&rcThumb);

	rcEdge = rcThumb;
	rcEdge.InflateRect(8,2);//绘制滑块外边矩形

	//以滑块为研究对象
	int nLength = rcTotal.Width()-rcEdge.Width();//滑块可以移动的最大范围

	//将单击的位置转换为滑块上的刻度：
	int nPos,nMin,nMax;
	GetRange(nMin,nMax);
	
	nPos = point.x* (nMax - nMin)/nLength - 8 *(nMax - nMin)/nLength;
	TRACE("nMax=%d,nMin=%d,nLength=%d,point.x=%d,nPos=%d\r\n",nMax,nMin,nLength,point.x,nPos);
	SetPos(nPos);
	m_bTrack = TRUE;
	Invalidate(FALSE);


	CSliderCtrl::OnLButtonDown(nFlags, point);
}


void CMySliderCtrl::OnLButtonUp(UINT nFlags, CPoint point)
{
	CRect rcThumb;
	GetThumbRect(&rcThumb);//获得滑块的矩形大小

	m_bTrack = rcThumb.PtInRect(point);
	Invalidate(FALSE);

	CSliderCtrl::OnLButtonUp(nFlags, point);
}


void CMySliderCtrl::OnMouseMove(UINT nFlags, CPoint point)
{
	CRect rcThumb;
	GetThumbRect(&rcThumb);//获得滑块的矩形大小

	BOOL bTrack;
	if (nFlags & MK_LBUTTON)
	{
		bTrack = TRUE;
	}else{
		if (rcThumb.PtInRect(point))
		{
			bTrack = TRUE;
		}else{
			bTrack = FALSE;
		}
	}

	if (m_bTrack != bTrack)
	{
		m_bTrack = bTrack;
	}

	//TRACE("trach=%d\r\n",m_bTrack);

	Invalidate(FALSE);

	CSliderCtrl::OnMouseMove(nFlags, point);
}


void CMySliderCtrl::OnPaint()
{
	CPaintDC dc(this); 

	CRect rcTotal;
	GetClientRect(&rcTotal);

	int nCurPos = 0,nMin = 0,nMax = 0;
	nCurPos = GetPos();
	GetRange(nMin,nMax);

	//绘制滑过的区域
	CRect rcDraw = rcTotal;
	rcDraw.right = nCurPos * rcTotal.Width()/(nMax - nMin);
	dc.FillSolidRect(&rcDraw,RGB(148,250,148));

	//绘制剩下没滑过的区域
	rcDraw.left = rcDraw.right;
	rcDraw.right = rcTotal.right;
	dc.FillSolidRect(&rcDraw,RGB(132,174,148));

	CRect rcThumb,rcEdge;
	GetThumbRect(&rcThumb);//得到滑块的位置

	CBrush br;
	if(m_bTrack) br.CreateSolidBrush(RGB(247,166,8));//热点颜色
	else         br.CreateSolidBrush(RGB(82,215,33));//非热点颜色
	dc.SelectObject(&br);

	CPen pen(PS_SOLID,1,RGB(0,128,0));
	dc.SelectObject(&pen);

	rcEdge = rcThumb;
	rcEdge.InflateRect(8,2);//绘制滑块外边矩形
	
	dc.RoundRect(&rcEdge,CPoint(10,10));
	dc.FillSolidRect(&rcThumb,RGB(200,100,100));//绘制滑块
	
}


BOOL CMySliderCtrl::OnEraseBkgnd(CDC* pDC)
{
	return TRUE;//停止刷新背景，防止闪烁

	//return CSliderCtrl::OnEraseBkgnd(pDC);
}