c++ 滚动条到窗口

Question

嘿，我在这里创建一个窗口： _hWnd = CreateWindowEx( WS_EX_CLIENTEDGE, //dwExStyle (LPCWSTR) _wndClass, //lpClassName L"", //lpWindowName WS_儿童 | WS_HSCROLL | WS_VSCROLL , //dwStyle CW_USEDEFAULT, //X CW_USEDEFAULT, //是 200, //n宽度 150, //n高度 hWndParent, //hWndParent NULL, //hMenu hInstance, //hInstance NULL //lp参数 );

我添加了滚动条 (WS_HSCROLL | WS_VSCROLL)，但我该如何控制它们？

Answer 1

我认为你应该参考 MSDN 以获取更多信息，但这里是我一天写的一小段代码（只是为了让你从一些东西开始）。

一般来说，这个想法是关于在 WindowProcedure 例程中处理特定消息（WM_HSCROLL、WM_VSCROLL）。评估新滚动条位置的最简单方法（我的意思是 WinAPI 方法）是使用特定的SCROLLINFO 结构。在下面的代码块中，使用了SCROLLINFO si。

  case WM_HSCROLL:
    {
      TEXTHANDLER * handler = ((TEXTHANDLER *)GetProp(hWnd, "TEXTHANDLER"));

      // If user is trying to scroll outside
      // of scroll range, we don't have to
      // invalidate window
      BOOL needInvalidation = TRUE;

      if (handler->renderer->wordWrap)
      {
        return 0;
      }

      si.cbSize = sizeof(si);
      si.fMask  = SIF_ALL;
      GetScrollInfo(hWnd, SB_HORZ, &si);

      switch (LOWORD(wParam))
      {
      case SB_LINELEFT: 
        si.nPos -= 1;
        if (si.nPos < 0)
        {
          si.nPos = 0;
          needInvalidation = FALSE;
        }
        break;

      case SB_LINERIGHT: 
        si.nPos += 1;
        if (si.nPos > si.nMax)
        {
          si.nPos = si.nMax;
          needInvalidation = FALSE;
        }
        break;

      case SB_THUMBTRACK: 
        si.nPos = si.nTrackPos;
        break;
      }

      si.fMask = SIF_POS;
      SetScrollInfo(hWnd, SB_HORZ, &si, TRUE);

      // Set new text renderer parameters
      handler->renderer->xPos = si.nPos;

      if (needInvalidation) InvalidateRect(hWnd, NULL, FALSE);
      return 0;
  }

  case WM_VSCROLL:
    {
      TEXTHANDLER * handler = ((TEXTHANDLER *)GetProp(hWnd, "TEXTHANDLER"));

      BOOL needInvalidation = TRUE;

      si.cbSize = sizeof(si);
      si.fMask  = SIF_ALL;
      GetScrollInfo(hWnd, SB_VERT, &si);

      switch (LOWORD(wParam))
      {
      case SB_LINEUP: 
        si.nPos -= 1;
        if (si.nPos < 0)
        {
          si.nPos = 0;
          needInvalidation = FALSE;
        }
        break;

      case SB_LINEDOWN: 
        si.nPos += 1;
        if (si.nPos > si.nMax)
        {
          si.nPos = si.nMax;
          needInvalidation = FALSE;
        }
        break;

      case SB_PAGEUP:
        si.nPos -= handler->renderer->cyCount;
        if (si.nPos < 0)
        {
          si.nPos = 0;
          needInvalidation = FALSE;
        }
        break;

      case SB_PAGEDOWN:
        si.nPos += handler->renderer->cyCount;
        if (si.nPos > si.nMax)
        {
          si.nPos = si.nMax;
          needInvalidation = FALSE;
        }
        break;

      case SB_THUMBTRACK: 
        si.nPos = si.nTrackPos;
        break;
      }

      si.fMask = SIF_POS;
      SetScrollInfo(hWnd, SB_VERT, &si, TRUE);

      // Set new text renderer parameters
      handler->renderer->yPos = si.nPos;

      if (needInvalidation) InvalidateRect(hWnd, NULL, FALSE);
      return 0;
    }