ScrollBar的消息处理

ScrollBar的消息处理 ScrollBar分成窗口的ScrollBar，和单独的ScrollBar两种，处理方式有所不同，但差别不大。 如果是窗口的ScrollBar，OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar) 中的pScrollBar为NULL，要用GetScrollLimit(SB_VERT); 如果是控件的就用SB_CTL与之对应。 下面是CMySVView（从CView继承）的消息处理（参考MSDN）框架 void CMySVView::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar) { // Get the minimum and maximum scroll-bar positions. int minpos; int maxpos; GetScrollRange(SB_VERT, &minpos, &maxpos); maxpos = GetScrollLimit(SB_VERT); // Get the current position of scroll box. int curpos = GetScrollPos(SB_VERT); // Determine the new position of scroll box. switch (nSBCode) { case SB_TOP: // Scroll to far TOP. curpos = minpos; break; case SB_BOTTOM: // Scroll to far BOTTOM. curpos = maxpos; break; case SB_ENDSCROLL: // End scroll. break; case SB_LINEUP: // Scroll UP. if (curpos > minpos) curpos--; break; case SB_LINEDOWN: // Scroll DOWN. if (curpos < maxpos) curpos++; break; case SB_PAGEUP: // Scroll one page UP. { // Get the page size. SCROLLINFO info; GetScrollInfo(SB_VERT, &info, SIF_ALL); if (curpos > minpos) curpos = max(minpos, curpos - (int) info.nPage); } break; case SB_PAGEDOWN: // Scroll one page DOWN. { // Get the page size. SCROLLINFO info; GetScrollInfo(SB_VERT, &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_VERT, curpos); CView::OnVScroll(nSBCode, nPos, pScrollBar); } void CMySVView::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); }