TEXT宏的問題

[wangyangcheng]

//define A
1
2; //這樣不寫在一行又不可以!

#include <windows.h>
#include <stdio.h>
int main()
{
static TCHAR szBuffer[] = TEXT( "I am here!" )
TEXT( "Programming" );
//為什么這種寫法是合法的?兩個宏不寫在一行﹐可以嗎?為什么?
printf( "%s\n", szBuffer );
return 0;
}




問題二﹕
在這樣一個簡單的Windows程序中﹕
/*------------------------------------------------------------------------

HELLOWIN.C -- Displays "Hello, Windows 98!" in client area

(c) Charles Petzold, 1998

-----------------------------------------------------------------------*/



#include <windows.h>
LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,PSTR szCmdLine,int iCmdShow)
{
static TCHAR szAppName[] = TEXT("HelloWin");
HWND hwnd;
MSG msg;
WNDCLASS wndclass ;
wndclass.style = CS_HREDRAW|CS_VREDRAW;
wndclass.lpfnWndProc = WndProc;
wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;
wndclass.hInstance = hInstance;
wndclass.hIcon = LoadIcon(NULL,IDI_APPLICATION);
wndclass.hCursor = LoadCursor(NULL,IDC_ARROW);
wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.lpszMenuName = NULL;
wndclass.lpszClassName = szAppName;
if (!RegisterClass(&wndclass))
{
MessageBox(NULL,TEXT("This program requires Windows NT!"),szAppName,MB_ICONERROR);
return 0;
}
hwnd = CreateWindow(szAppName, //window class name
TEXT("The Hello Program"), //window caption
WS_OVERLAPPEDWINDOW, //window style
CW_USEDEFAULT, //initial x position
CW_USEDEFAULT, //initial y position
CW_USEDEFAULT, //initial x size
CW_USEDEFAULT, //initial y size
NULL, //parent window handle
NULL, //window menu handle
hInstance, //program instance handle
NULL); //creation parameters

ShowWindow(hwnd,iCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&msg,NULL,0,0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM IParam)
{
HDC hdc;
PAINTSTRUCT ps;
RECT rect;
static int cxChar,cyChar;
switch(message)
{
case WM_CREATE:
PlaySound(TEXT("hellowin.wav"),NULL,SND_FILENAME|SND_ASYNC);
hdc = GetWindowDC(hwnd);
TEXTMETRIC tm;
GetTextMetrics(hdc,&tm);
cxChar = tm.tmAveCharWidth ;
cyChar = tm.tmHeight + tm.tmExternalLeading ;
ReleaseDC(hwnd,hdc);

return 0;
case WM_PAINT:
hdc = BeginPaint(hwnd,&ps);
// InvalidateRect(hwnd,NULL,TRUE);
GetClientRect(hwnd,&rect);
TextOut(hdc,300,201,TEXT("Hello,World!"),12);
DrawText(hdc,TEXT("Hello,Windows98!"),-1,&rect,
DT_SINGLELINE|DT_CENTER|DT_VCENTER);
EndPaint(hwnd,&ps);
return 0;

case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd,message,wParam,IParam);
//DefWindowProc()到底做了些什么?
//如果注釋這一行﹐則窗口都不會生成﹐比如說接受ALT-F4的
//鍵盤消息﹐也是由它來處理嗎?
}

[lzzqqq]

DefWindowProc();
处理Windows消息啊！！
ALT-F4是由它来处理的，Windows发现你在你窗口上按ALT_F4,就发送WM_CLOSE给你窗口
窗口调用你写的WndProc
然后你写的WndProc调用用DefWindowProc
然后DefWindowProc发送WM_DESTORY到窗口 //
窗口调用你写的WndProc

[马丁当]

第一个问题。
应该这样写，
#define A 1
宏定义以同在一行内的的有效。

static TCHAR szBuffer[] = TEXT( "I am here!" )
TEXT( "Programming" );
是为字符串付初值，当字符串较长时，可用空白字符断开（包括换行符，制表符）
跟宏没关系。
static char szBuffer[] = "i am here!Programming"
与下面的等效
static char szBuffer[] = "i am here!"
"Programming"
static char szBuffer[] = "i am here!" "Programming"

[马丁当]

第二个问题
　因为在你的回调函数里不可能处理所有的窗口消息。
所以你只要处理完你需要处理的消息，其它的就交给DefWindowProc去处理了。
所以不能注释掉

[wangyangcheng]

Thanks a lot!