MFC学习之路(4)之对话框自带滚动条的使用

       最近在整理一个别人的MFC程序的时候，发现对话框太大了，屏幕显示不下，最后决定加一个对话框自带的滚动条，以垂直滑动条为例，具体操作如下：
1.添加垂直滑动条：右键对话框——>属性,将Vertical Scrollbar状态改为True。
                                   
2.添加响应函数：右键对话框——>添加类向导

3.在OnInitDialog()函数中添加

  SCROLLINFO scrollinfo;
  GetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
  scrollinfo.nPage=10; //设置滑块大小
  scrollinfo.nMax=100; //设置滚动条的最大位置0–100
  SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);

4 .在OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)消息处理函数中添加：

void CChangeonDlg::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)   //对话框的滚动效果
{
    // TODO: 在此添加消息处理程序代码和/或调用默认值

    SCROLLINFO scrollinfo;
    GetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
    int unit=3;        
     switch (nSBCode)  
     {      
     case SB_LINEUP:          //Scroll one line up
         scrollinfo.nPos -= 1;  
         if (scrollinfo.nPos<scrollinfo.nMin)
         {  
             scrollinfo.nPos = scrollinfo.nMin;  
             break;  
         }  
         SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);  
         ScrollWindow(0,unit); 
         break;  
     case SB_LINEDOWN:           //Scroll one line down
         scrollinfo.nPos += 1;  
         if (scrollinfo.nPos+scrollinfo.nPage>scrollinfo.nMax)  //此处一定要注意加上滑块的长度，再作判断
         {  
             scrollinfo.nPos = scrollinfo.nMax;  
             break;  
         }  
         SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);  
         ScrollWindow(0,-unit);  
         break;  
     case SB_PAGEUP:            //Scroll one page up.
         scrollinfo.nPos -= 5;  
         if (scrollinfo.nPos<=scrollinfo.nMin)
         {  
             scrollinfo.nPos = scrollinfo.nMin;  
             break;  
         }  
         SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);  
         ScrollWindow(0,unit*5);  
         break;  
     case SB_PAGEDOWN:        //Scroll one page down        
         scrollinfo.nPos += 5;  
         if (scrollinfo.nPos+scrollinfo.nPage>=scrollinfo.nMax)  //此处一定要注意加上滑块的长度，再作判断
         {  
             scrollinfo.nPos = scrollinfo.nMax;  
             break;  
         }  
         SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);  
         ScrollWindow(0,-unit*5);  
         break;  
     case SB_ENDSCROLL:      //End scroll     
         break;  
     case SB_THUMBPOSITION:  //Scroll to the absolute position. The current position is provided in nPos
         break;  
     case SB_THUMBTRACK:                  //Drag scroll box to specified position. The current position is provided in nPos
         ScrollWindow(0,(scrollinfo.nPos-nPos)*unit);  
         scrollinfo.nPos = nPos;  
         SetScrollInfo(SB_VERT,&scrollinfo,SIF_ALL);
         break;  
     }

    CDialog::OnVScroll(nSBCode, nPos, pScrollBar);
}

5 .效果展示：