WM_SIZE

procedure WMSize (var Message: TWMSize);  message WM_SIZE;

参数说明

wParam:

Specifies the type of resizing requested.

通常用来向别的窗口发送消息时,需要指定的附加信息

Value	Meaning
SIZE_MAXHIDE	Message is sent to all pop-up windows when some other window is maximized.
SIZE_MAXSHOW	Message is sent to all pop-up windows when some other window has been restored to its former size.
SIZE_MINIMIZED	The window has been minimized.
Value	Meaning
SIZE_RESTORED	The window has been resized, but neither the SIZE_MINIMIZED nor SIZE_MAXIMIZED value applies.

lParam:

The low-order word of lParamspecifies the new width of the client area.

The high-order word of lParam specifies the new height of the client area.

note:

lParam和GetClientRect的功能一样,有时候WM_SIZE的效率要比使用GetClientRect高. 可以在程序中使用WM_SIZE来保存Client area的大小方便以后使用.

WM_SIZE后于WM_CREATE消息!!在窗口被创建时的顺序!

WM_SIZE附带的信息:

WM_SIZE

fwSizeType = wParam; // resizing flag

nWidth = LOWORD(lParam); // width of client area

nHeight = HIWORD(lParam); // height of client area

告诉我们Windows处理窗口大小变化后新窗口客户区的大小.

Message Cracker

void Cls_OnSize(HWND hwnd, UINT state, int cx, int cy)

...{

//do ...

}

参数cx,cy是新窗口客户区的大小!宽度和高度

注意cx，cy最好定义为全局或是静态的，例子如下

static UINT cx,cy;

switch (message)

{

case WM_SIZE:

cx=LOWORD(lParam);

cy=HIWORD(lParam);

break;

http://www.cnblogs.com/toosuo/p/3387827.html