关于消息?

[Michaelyfj]

如何处理SendMessage函数中wParam参数的高低位？
如消息: WM_VSCROLL
nScrollCode = (int) LOWORD(wParam); // 低位：scroll bar value
nPos = (short int) HIWORD(wParam); // 高位：scroll box position
hwndScrollBar = (HWND) lParam; // handle to scroll bar
怎样组织nScrollCode和nPos的值？

[ccpyccpy]

关注

[Michaelyfj]

帖子加分(百分大放送)

[zcheny]

这要看你想Send什么消息，事实上Delphi为每个消息都定义了相应的Record类型来方便地处理高低位，如WM_VSCROLL有相应的TWMScroll,其定义为
TWMScroll = packed record
Msg: Cardinal;
ScrollCode: Smallint; { SB_xxxx }
Pos: Smallint;
ScrollBar: HWND;
Result: Longint;
end;
再如WM_PAINT,
TWMPaint = packed record
Msg: Cardinal;
DC: HDC;
Unused: Longint;
Result: Longint;
end;

你只需要在Messages单元查找一下就可以了。请参考Delphi的Source Code。

[Michaelyfj]

喔!