windows窗口和子窗口消息传递的有关问题

#include <windows.h>
struct
{
        
           int                   iStyle ;
        
           TCHAR *               szText ;
        
}
button[] =
        
{
        
           BS_PUSHBUTTON,        TEXT ("PUSHBUTTON"),
        
           BS_DEFPUSHBUTTON,     TEXT ("DEFPUSHBUTTON"),
        
           BS_CHECKBOX,          TEXT ("CHECKBOX"),
        
           BS_AUTOCHECKBOX,         TEXT ("AUTOCHECKBOX"),
        
           BS_RADIOBUTTON,       TEXT ("RADIOBUTTON"),
        
           BS_3STATE,            TEXT ("3STATE"),
        
           BS_AUTO3STATE,        TEXT ("AUTO3STATE"),
        
           BS_GROUPBOX,          TEXT ("GROUPBOX"),
        
           BS_AUTORADIOBUTTON,      TEXT ("AUTORADIO"),
        
           BS_OWNERDRAW,            TEXT ("OWNERDRAW")
        
} ;
        

#define NUM (sizeof button / sizeof button[0])

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = "My firest window form application";

int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nFunsterStil)

{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default color as the background of the window */
    HBRUSH br = CreateSolidBrush(RGB(255,255,255));
    wincl.hbrBackground = br;
   // wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           "My firest windows form application",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           800,                 /* The programs width */
           600,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nFunsterStil);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{        
    static int iCount;
       static HWND  hwndButton[NUM] ;
       static RECT  rect ;
       static TCHAR  szTop[] = TEXT ("message   wParam  lParam"),
       szUnd[] = TEXT ("_______   ______  ______"),
       szFormat[] = TEXT ("%-16s%04X-%04X   %04X-%04X"),
       szBuffer[50] ;
       static int cxChar, cyChar ;
       int i;
    char *p;
    p = "abckefsdf";
    HDC hdc;
    PAINTSTRUCT ps;
    switch (message)                  /* handle the messages */
    {  case  WM_CREATE :
              cxChar = LOWORD (GetDialogBaseUnits ()) ;
              cyChar = HIWORD (GetDialogBaseUnits ()) ;
              for (i = 0 ; i < NUM ; i++)
                    hwndButton[i] =CreateWindow ( TEXT("button"),button[i].szText,
                    WS_CHILD | WS_VISIBLE | button[i].iStyle,
                    cxChar, cyChar * (1 + 2 * i),  20 * cxChar, 7 * cyChar / 4,hwnd, (HMENU) i,
                    ((LPCREATESTRUCT) lParam)->hInstance, NULL) ;
              return 0 ;
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        case WM_PAINT:
                InvalidateRect (hwnd, &rect, TRUE) ;
                hdc = BeginPaint (hwnd, &ps) ;
                
            TextOut(hdc,50,100,"刘备",0);
                TextOut(hdc,50,100,TEXT("xxy"),0);
                SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT)) ;
                SetBkMode (hdc, TRANSPARENT) ;
                TextOut (hdc, 24 * cxChar, cyChar, szTop, lstrlen (szTop)) ;
                TextOut (hdc, 24 * cxChar, cyChar, szUnd, lstrlen (szUnd)) ;
                EndPaint (hwnd, &ps) ;
                return 0 ;
        case WM_LBUTTONDOWN:
            iCount = 0;
            InvalidateRect(hwnd,NULL,TRUE);
            TextOut(hdc,50,100,"刘备",0);
            break;
        case WM_RBUTTONDOWN:
            break;
        case WM_SIZE:
            rect.left = 24 * cxChar ;
            rect.top =  2 * cyChar ;
            rect.right = LOWORD (lParam) ;
            rect.bottom = HIWORD (lParam) ;
            return 0 ;
        case WM_COMMAND :   
            ScrollWindow (hwnd, 0, -cyChar, &rect, &rect) ;
            hdc = GetDC (hwnd) ;
            SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT)) ;
            TextOut(hdc, 24 * cxChar, cyChar * (rect.bottom / cyChar - 1),szBuffer,wsprintf (szBuffer, szFormat,
                    message == WM_DRAWITEM ? TEXT ("WM_DRAWITEM") :TEXT ("WM_COMMAND"),
                    HIWORD (wParam), LOWORD (wParam),
                    HIWORD (lParam), LOWORD (lParam))) ;
            ReleaseDC (hwnd, hdc) ;
            ValidateRect (hwnd, &rect) ;
           break ;
        default:                      /* for messages that we don't deal with */
                return DefWindowProc (hwnd, message, wParam, lParam);
    }
    return 0;
}