MFC對話框中滾動條的使用

在對話框中增加一個滾動條控件，添加相應的相應消息的時候，碰到一個效果。

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

	//////////////////////////////////////////////////////////////////////////
	SetScrollRange(SB_HORZ, 0, 10);

	return TRUE;  // return TRUE  unless you set the focus to a control
}

竟然出現了整個對話框的滾動條。實際上，就是我使用滾動條錯誤造成的，在初始化中要改。不是上面代碼。

要寫成下面的

((CScrollBar*)GetDlgItem(IDC_SCROLLBAR1))->SetScrollRange(0, 10);

滾動條的消息函數就參考MSDN上的示例些就好了。示例代碼如下

void CMdiView::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
   // Get the minimum and maximum scroll-bar positions.
   int minpos;
   int maxpos;
   GetScrollRange(SB_HORZ, &minpos, &maxpos); 
   maxpos = GetScrollLimit(SB_HORZ);

   // Get the current position of scroll box.
   int curpos = GetScrollPos(SB_HORZ);

   // Determine the new position of scroll box.
   switch (nSBCode)
   {
   case SB_LEFT:      // Scroll to far left.
      curpos = minpos;
      break;

   case SB_RIGHT:      // Scroll to far right.
      curpos = maxpos;
      break;

   case SB_ENDSCROLL:   // End scroll.
      break;

   case SB_LINELEFT:      // Scroll left.
      if (curpos > minpos)
         curpos--;
      break;

   case SB_LINERIGHT:   // Scroll right.
      if (curpos < maxpos)
         curpos++;
      break;

   case SB_PAGELEFT:    // Scroll one page left.
   {
      // Get the page size. 
      SCROLLINFO   info;
      GetScrollInfo(SB_HORZ, &info, SIF_ALL);

      if (curpos > minpos)
      curpos = max(minpos, curpos - (int) info.nPage);
   }
      break;

   case SB_PAGERIGHT:      // Scroll one page right.
   {
      // Get the page size. 
      SCROLLINFO   info;
      GetScrollInfo(SB_HORZ, &info, SIF_ALL);

      if (curpos < maxpos)
         curpos = min(maxpos, curpos + (int) info.nPage);
   }
      break;

   case SB_THUMBPOSITION: // Scroll to absolute position. nPos is the position
      curpos = nPos;      // of the scroll box at the end of the drag operation.
      break;

   case SB_THUMBTRACK:   // Drag scroll box to specified position. nPos is the
      curpos = nPos;     // position that the scroll box has been dragged to.
      break;
   }

   // Set the new position of the thumb (scroll box).
   SetScrollPos(SB_HORZ, curpos);

   CView::OnHScroll(nSBCode, nPos, pScrollBar);
}

我的滾動條只需要做到，按住滾動條一種操作，擡起鼠標就停止。所以就把多餘的給刪掉了

void CTestDialogProDlg::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
	// Get the minimum and maximum scroll-bar positions.
	int minpos;
	int maxpos;
	pScrollBar->GetScrollRange(&minpos, &maxpos); 
	// Get the current position of scroll box.
	int curpos = pScrollBar->GetScrollPos();
	// Determine the new position of scroll box.
	switch (nSBCode)
	{
	case SB_ENDSCROLL:   // End scroll.//鼠標擡起
		break;
	case SB_LINELEFT:      // Scroll left.//按住左端按鈕
		if (curpos > minpos)
			curpos--;
		else
			curpos = maxpos;

		break;
	case SB_LINERIGHT:   // Scroll right.//按住右端按鈕
		if (curpos < maxpos)
			curpos++;
		else
			curpos = minpos;
		break;
	}
	// Set the new position of the thumb (scroll box).
	pScrollBar->SetScrollPos(curpos);

	CDialogEx::OnHScroll(nSBCode, nPos, pScrollBar);
}

在消息函數中，CScrollBar* pScrollBar這個參數就是對應操作的滾動條控件，如果是空，就是界面帶的那個控件。MSDN說明如下

這個就提供了多個滾動條操作的方法。