C/C++：Windows编程—MFC基于CWnd自绘CListCtrl控件且带滚动条

水深无声 2023-07-05 14:57 142阅读 0赞

### 文章目录 ###

*   *  前言
     *  效果图
     *  代码思路
     *  滚动条思路
     *  完整代码

## 前言 ##

由于工作需要，需要**自绘类似CListCtrl那种控件 而且每项能带类似按钮的点击事件**。所以笔者去进行研究，费了点时间写了个简单的自绘窗口 顺带也研究了下滚动条。博主在网络搜索的时候经常遇到只有代码没有效果图，这样有意思吗，既然都写了 弄全一点不行吗。**在这里也呼吁一下广大博友，写博客的时候都把效果图带上**。我们也先看效果图。

## 效果图 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI5NTQyNjEx_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI5NTQyNjEx_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI5NTQyNjEx_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI5NTQyNjEx_size_16_color_FFFFFF_t_70 3]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzI5NTQyNjEx_size_16_color_FFFFFF_t_70 4]

## 代码思路 ##

和题目想呼应，这里我们绘制的CMyListWnd窗口，是基于CWnd类。这样可以最大发挥我们的自由度，可以完全自由发挥。直接在MFC项目添加类->MFC类，这样添加的类就直接继承CWnd类了，免的自己写错。博主绘制窗口是在**BOOL CMyListWnd::OnEraseBkgnd(CDC\* pDC)** 回调函数中，因为该函数自带CDC参数直接用就行了。

博主绘制使用的gdi+相关API进行绘制的。gdi+简单例子demo可以参考这个 [https://blog.csdn.net/shaoyubin999/article/details/84143222][https_blog.csdn.net_shaoyubin999_article_details_84143222]。绘制list内容实上际比较简单，一行一行绘制，按钮效果也比较好弄，就是鼠标悬停到按钮区域是 将鼠标样式改为鼠标手，然后按钮点击处理逻辑，博主是在 **void CMyListWnd::OnLButtonUp(UINT nFlags, CPoint point)** 回调函数中处理的，判断鼠标此时位置是否在 按钮区域然后做的处理。

废话太多，怕大家看不下去，下面直接是OnEraseBkgnd代码。其实最复杂的是滚动条绘制和滚动条功能的实现，思路看下一节。

/*
    当CWnd对象的背景需要被擦除时（例如，当窗口大小被改变时），框架就调用这个函数。它被调用以便为绘图准备无效区域。
    如果重载的OnEraseBkgnd在响应WM_ERASEBKGND时处理了这个消息并擦除了背景，则应当返回非零值，表明不需要进一步擦除。(实际上就是在这里可以绘图，并且返回TRUE)
    */
    BOOL CMyListWnd::OnEraseBkgnd(CDC* pDC)
    {
    	HDC hMemDC = CreateCompatibleDC( pDC->m_hDC ); 
    	
    	if(m_iTotalDrawHeight<m_iWndHeight) m_iTotalDrawHeight=m_iWndHeight;
    
    	HBITMAP hMemBitmap = CreateCompatibleBitmap( pDC->m_hDC, m_iWndWidth, m_iTotalDrawHeight);  
    	SelectObject(hMemDC, hMemBitmap); 
    
    	Graphics graph( hMemDC );
    	//graph.SetSmoothingMode(SmoothingModeHighQuality);
    	//graph.SetTextRenderingHint( TextRenderingHintAntiAliasGridFit );
    	graph.SetSmoothingMode(SmoothingModeAntiAlias);
    	graph.SetTextRenderingHint( TextRenderingHintClearTypeGridFit );
    
    
    	SolidBrush solidBrushBlack( Color(250,0,0,0) );
    	SolidBrush solidBrushBlack2( Color( 200,240,240,240) );
    	SolidBrush solidBrushGray( Color( 255,225,225,225) );
    	SolidBrush solidBrushWhite( Color(255,255,255,255) );
    	SolidBrush solidBrushGrayText( Color( 250, 167, 167, 167 ) );
    	//设置字体相关
    	FontFamily fontFamily( m_strfontFamily );
    	Gdiplus::Font fontRegular( &fontFamily, 13, FontStyleRegular,UnitPixel );
    	Gdiplus::Font fontRegular2( &fontFamily, 12, FontStyleRegular,UnitPixel );
    
    	StringFormat sf,sf2;
    	sf.SetAlignment(StringAlignmentNear);
    	sf.SetLineAlignment( StringAlignmentCenter );
    
    	// 居中
    	sf2.SetAlignment(StringAlignmentCenter);
    	sf2.SetLineAlignment( StringAlignmentCenter );
    
    	graph.FillRectangle( &solidBrushWhite, -1, -1, m_iWndWidth+1, m_iTotalDrawHeight+1 );
    	
    
    
    	// 每行高30
    	UINT nCount = m_iTotalDrawHeight/m_iItemHeight;
    	for( UINT i = 0; i < nCount ; i++ )
    	{
    		UINT y = m_iItemHeight*(i);
    		if ( i%2 != 0 )
    		{
    			graph.FillRectangle( &solidBrushBlack2, 0, y, m_iWndWidth, m_iItemHeight );
    		}
    	}
    
    	m_iDrawHeight = m_Items.size() * m_iItemHeight;
    
    	std::list<CMyListItem>::iterator it = m_Items.begin();
    	UINT i = 0;
    	int btnRight = 20; // 最右边按钮距离容器右边框距离
    	int btnTop = 3;    // 按钮距离每行上边的距离
    	int btnJianGe = 5;
    	int btnWidth = 30,btnHeight = 24; // item 高为30
    	for(;it != m_Items.end(); it ++,i++)
    	{
    		UINT y = m_iItemHeight*(i);
    		CString strtemp = it->m_strText;
    		graph.DrawString( strtemp, strtemp.GetLength(), &fontRegular, it->m_rcRect, &sf, &solidBrushBlack );
    		
    		// 自己画 可以点击的按钮, 
    		// 复制
    		graph.FillRectangle( &solidBrushGray,it->m_rcBtn1);
    		graph.DrawString( it->m_strBtn1, it->m_strBtn1.GetLength(), &fontRegular2, it->m_rcBtn1,&sf2, &solidBrushBlack);
    		// 删除
    		graph.FillRectangle( &solidBrushGray, it->m_rcBtn2 );
    		graph.DrawString( it->m_strBtn2, it->m_strBtn2.GetLength(), &fontRegular2, it->m_rcBtn2,&sf2, &solidBrushBlack);
    	}
    	
    
    	int scrollWidth = 15;// 滚动条背景宽度
    	// 滑动条
    	if ( m_iDrawHeight > m_iWndHeight )
    	{
    		m_bDrawScroll = TRUE;
    		SolidBrush solidbrushGray( Color( 150,150,150) );
    		Pen penBroder( Color(180,180,180), 1.0 );
    
    		// 画滚动条背景
    		graph.FillRectangle( &solidBrushWhite, m_iWndWidth-scrollWidth, m_iDrawOffset, scrollWidth, m_iWndHeight  ); // 填滑动条背景色
    		graph.DrawRectangle( &penBroder, m_iWndWidth-scrollWidth, m_iDrawOffset+1, scrollWidth-1, m_iWndHeight-2 ); // 画滑动条边框
    
    		// 计算滚动块大小位置
    		double dDate = (double)m_iWndHeight/(double)m_iDrawHeight;
    		int nScroll = int(m_iWndHeight*dDate); // 滑块高度
    
    		SolidBrush solidbrushScroll( Color( 200,200,200) );
    		Pen pen( Color( 0,0,0 ) );
    		// 画滑块
    		graph.FillRectangle( &solidbrushScroll, m_iWndWidth-scrollWidth, m_iDrawOffset+(INT)(m_iDrawOffset*dDate), scrollWidth, nScroll ); // 填充滑块颜色
    		int mid = m_iDrawOffset+(INT)(m_iDrawOffset*dDate)+nScroll/2;  
    		//graph.DrawLine( &pen, m_iWndWidth-7, mid-4, m_iWndWidth-3, mid-4 );
    		//graph.DrawLine( &pen, m_iWndWidth-8, mid, m_iWndWidth-2, mid );
    		//graph.DrawLine( &pen, m_iWndWidth-7, mid+4, m_iWndWidth-3, mid+4  );
    		graph.DrawRectangle( &penBroder, m_iWndWidth-scrollWidth, m_iDrawOffset+1+(INT)(m_iDrawOffset*dDate), scrollWidth-1, nScroll-2 ); // 画滑块边框
    
    		// 滑块矩形设置
    		m_rectScroll.SetRect( m_iWndWidth-scrollWidth, (int)(m_iDrawOffset*dDate), m_iWndWidth, (int)(m_iDrawOffset*dDate)+nScroll  );
    	}
    	else 
    	{
    		m_bDrawScroll = FALSE;
    		m_iDrawOffset = 0;
    	}
    
    
    	Pen pen( Color(255,0,0 ),1.0);
    	graph.DrawRectangle( &pen, 1, 1, m_iWndWidth-2, m_iTotalDrawHeight-2 );
    
    	DeleteObject(hMemBitmap);  
    	//BitBlt( pDC->m_hDC, 0, 0, m_iWndWidth, m_iWndHeight, hMemDC, 0, 0, SRCCOPY);  
    	BitBlt( pDC->m_hDC, -1, -1, m_iWndWidth+1, m_iWndHeight, hMemDC, 0, m_iDrawOffset, SRCCOPY ); 
    	DeleteDC( hMemDC);
    	return TRUE;
    }

## 滚动条思路 ##

自己结合网络上所学知识 所融会的思路，自己打的草稿，自己可以研究完整代码，已经是比较简单的demo了。

绘制滚动条 原理
    
    m_iWndHeight 给的高度 
    m_iDrawHeight 内容(需要绘制)的高度 可超过实际高度 这时就需要滚动条了。
    m_iTotalDrawHeight 绘制的总高度，m_iTotalDrawHeight = m_iWndHeight if(m_iDrawHeight>m_iWndHeight) m_iTotalDrawHeight = m_iDrawHeight
    m_bDrawScroll 是否绘制滚动条 
    m_iDrawOffset 偏移位置(以初始位置为准，可正可负 不过为负的时候强制为0 不偏移，为正 超过最大偏移 强制为最大偏移)
    {
    	if ( m_iDrawOffset <=0 )
    	{
    		m_iDrawOffset = 0;
    	}
    	else if ( m_iDrawOffset > m_iDrawHeight - m_iWndHeight )
    	{
    		m_iDrawOffset  = m_iDrawHeight - m_iWndHeight;
    	}
    }
    nScroll 滑块高度 当m_iWndHeight ==  m_iDrawHeight 此时(如果规则让其显示的话)滑块长度为 m_iWndHeight 
    当m_iDrawHeight越长nScroll越小 算法如下
    {
    	double dData = m_iWndHeight/m_iDrawHeight; // 比率，用计算滑块长度、滑块偏移y位置
    	int nScroll = m_iWndHeight * dData;
    }
    m_rectScroll 滑块位置，用于鼠标移动使用
    
    绘制滚动条总的逻辑
    if(m_iDrawHeight > m_iWndHeight)
    {
    	m_bDrawScroll = true
    	
    	
    	// 绘制滚动条背景 
    	// 宽度自定，高度为自定 <= m_iWndHeight
    	// 位置(x自定) y是讲究，因为人眼看到滚动条背景是始终不动的，但是它同样也是位于总的内容窗口上
    	// 那就是说它的y是根据 m_iDrawOffset 来的！和内容偏移同样
    	graph.FillRectangle( &solidBrushWhite, m_iWndWidth-10, m_iDrawOffset, 10, m_iWndHeight  ); // 填滑动条背景色
    	graph.DrawRectangle( &penBroder, m_iWndWidth-10, m_iDrawOffset+1, 9, m_iWndHeight-2 ); // 画滑动条边框
    	
    	
    	// 绘制滑块，这个也是有讲究的
    	// 首先计算滑块的高度 在上面，宽度自定
    	// 滑块位置x 自定，y 是根据滚动条背景的y确定的 还加上 偏移位置*dData
    	滑块的y = m_iDrawOffset + m_iDrawOffset*dData
    	double dDate = (double)m_iWndHeight/(double)m_iDrawHeight;
    	int nScroll = int(m_iWndHeight*dDate); // 滑块高度
    	graph.FillRectangle( &solidbrushScroll, m_iWndWidth-10, m_iDrawOffset+(INT)(m_iDrawOffset*dDate), 10, nScroll ); // 填充滑块颜色
    	int mid = m_iDrawOffset+(INT)(m_iDrawOffset*dDate)+nScroll/2;  
    	graph.DrawLine( &pen, m_iWndWidth-7, mid-4, m_iWndWidth-3, mid-4 );
    	graph.DrawLine( &pen, m_iWndWidth-8, mid, m_iWndWidth-2, mid );
    	graph.DrawLine( &pen, m_iWndWidth-7, mid+4, m_iWndWidth-3, mid+4  );
    	graph.DrawRectangle( &penBroder, m_iWndWidth-10, m_iDrawOffset+1+(INT)(m_iDrawOffset*dDate), 9, nScroll-2 ); // 画滑块边框
    	
    	
    	// 设置滑块的绝对位置，用于鼠标移动使用
    	m_rectScroll.SetRect( m_iWndWidth-10, (int)(m_iDrawOffset*dDate), m_iWndWidth, (int)(m_iDrawOffset*dDate)+nScroll  );
    }
    else
    {
    		m_bDrawScroll = FALSE;
    		m_iDrawOffset = 0;
    }

## 完整代码 ##

[需要完整代码这里下载][Link 1]。

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[https_blog.csdn.net_shaoyubin999_article_details_84143222]: https://blog.csdn.net/shaoyubin999/article/details/84143222
[Link 1]: https://download.csdn.net/download/qq_29542611/12159562