询问《Windows程序设计》第五版关于键盘处理的例程

[lyrong]

/*--------------------------------------------------------
   KEYVIEW2.C -- Displays Keyboard and Character Messages
                 (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 ("KeyView2") ;
     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, TEXT ("Keyboard Message Viewer #2"),
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;
     
     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 lParam)
{
     static DWORD dwCharSet = DEFAULT_CHARSET ;       //这句是什么意思     
     static int   cxClientMax, cyClientMax, cxClient, cyClient, cxChar, cyChar ;
     static int   cLinesMax, cLines ;
     static PMSG  pmsg ;
     static RECT  rectScroll ;
     static TCHAR szTop[] = TEXT ("Message        Key       Char     ") //为什么有的字符数组定义，两个TEXT之间要用逗号：“TEXT(),TEXT();”，而有的不需要了？
                            TEXT ("Repeat Scan Ext ALT Prev Tran") ;
     static TCHAR szUnd[] = TEXT ("_______        ___       ____     ")
                            TEXT ("______ ____ ___ ___ ____ ____") ;

     static TCHAR * szFormat[2] = { 
          
               TEXT ("%-13s %3d %-15s%c%6u %4d %3s %3s %4s %4s"),
               TEXT ("%-13s            0x%04X%1s%c %6u %4d %3s %3s %4s %4s") } ; //这里TEXT之间用了逗号，为什么？但是为什么定义的时候不是“static TCHAR szFormat[2]=”而是“static TCHAR * szFormat[2]=”定义为指针？

     static TCHAR * szYes  = TEXT ("Yes") ;
     static TCHAR * szNo   = TEXT ("No") ;
     static TCHAR * szDown = TEXT ("Down") ;
     static TCHAR * szUp   = TEXT ("Up") ;

     static TCHAR * szMessage [] = { 
                         TEXT ("WM_KEYDOWN"),    TEXT ("WM_KEYUP"), 
                         TEXT ("WM_CHAR"),       TEXT ("WM_DEADCHAR"), 
                         TEXT ("WM_SYSKEYDOWN"), TEXT ("WM_SYSKEYUP"), 
                         TEXT ("WM_SYSCHAR"),    TEXT ("WM_SYSDEADCHAR") } ;
     HDC          hdc ;
     int          i, iType ;
     PAINTSTRUCT  ps ;
     TCHAR        szBuffer[128], szKeyName [32] ;
     TEXTMETRIC   tm ;

     switch (message)
     {
     case WM_INPUTLANGCHANGE: 
          dwCharSet = wParam ;
                                   // fall through
     case WM_CREATE:
     case WM_DISPLAYCHANGE:
     
               // Get maximum size of client area

          cxClientMax = GetSystemMetrics (SM_CXMAXIMIZED) ;
          cyClientMax = GetSystemMetrics (SM_CYMAXIMIZED) ;

              // Get character size for fixed-pitch font

          hdc = GetDC (hwnd) ;

          SelectObject (hdc, CreateFont (0, 0, 0, 0, 0, 0, 0, 0,
                                   dwCharSet, 0, 0, 0, FIXED_PITCH, NULL)) ; 
               
          GetTextMetrics (hdc, &tm) ;
          cxChar = tm.tmAveCharWidth ;
          cyChar = tm.tmHeight ;

          DeleteObject (SelectObject (hdc, GetStockObject (SYSTEM_FONT))) ;
          ReleaseDC (hwnd, hdc) ;

               // Allocate memory for display lines

          if (pmsg)
               free (pmsg) ;

          cLinesMax = cyClientMax / cyChar ;
          pmsg = malloc (cLinesMax * sizeof (MSG)) ;
          cLines = 0 ;
                                   // fall through
     case WM_SIZE:
          if (message == WM_SIZE)
          {
               cxClient = LOWORD (lParam) ;
               cyClient = HIWORD (lParam) ;
          }
               // Calculate scrolling rectangle

          rectScroll.left   = 0 ;
          rectScroll.right  = cxClient ;
          rectScroll.top    = cyChar ;
          rectScroll.bottom = cyChar * (cyClient / cyChar) ;//这里为什么不直接写成：“rectScroll.bottom = cyClient / cyChar ”呢？

          InvalidateRect (hwnd, NULL, TRUE) ;

          if (message == WM_INPUTLANGCHANGE)
               return TRUE ;//两句的作用是什么？如果输入法发生改变的消息在“case WM_INPUTLANGCHANGE”下就做了处理了啊？

          return 0 ;
          
     case WM_KEYDOWN:
     case WM_KEYUP:
     case WM_CHAR:
     case WM_DEADCHAR:
     case WM_SYSKEYDOWN:
     case WM_SYSKEYUP:
     case WM_SYSCHAR:
     case WM_SYSDEADCHAR: //这个消息有什么作用？

               // Rearrange storage array

          for (i = cLinesMax - 1 ; i > 0 ; i--)
          {
               pmsg[i] = pmsg[i - 1] ;
          }
               // Store new message

          pmsg[0].hwnd = hwnd ;
          pmsg[0].message = message ;
          pmsg[0].wParam = wParam ;
          pmsg[0].lParam = lParam ;

          cLines = min (cLines + 1, cLinesMax) ;

               // Scroll up the display

          ScrollWindow (hwnd, 0, -cyChar, &rectScroll, &rectScroll) ;

          break ;        // ie, call DefWindowProc so Sys messages work
          
     case WM_PAINT:
          hdc = BeginPaint (hwnd, &ps) ;

          SelectObject (hdc, CreateFont (0, 0, 0, 0, 0, 0, 0, 0,
                                   dwCharSet, 0, 0, 0, FIXED_PITCH, NULL)) ; 
          
          SetBkMode (hdc, TRANSPARENT) ;
          TextOut (hdc, 0, 0, szTop, lstrlen (szTop)) ;
          TextOut (hdc, 0, 0, szUnd, lstrlen (szUnd)) ;

          for (i = 0 ; i < min (cLines, cyClient / cyChar - 1) ; i++)
          {
               iType = pmsg[i].message == WM_CHAR ||
                       pmsg[i].message == WM_SYSCHAR ||
                       pmsg[i].message == WM_DEADCHAR ||
                       pmsg[i].message == WM_SYSDEADCHAR ;

               GetKeyNameText (pmsg[i].lParam, szKeyName, 
                               sizeof (szKeyName) / sizeof (TCHAR)) ;

               TextOut (hdc, 0, (cyClient / cyChar - 1 - i) * cyChar, szBuffer,
                        wsprintf (szBuffer, szFormat [iType],
                             szMessage [pmsg[i].message - WM_KEYFIRST],                   
                             pmsg[i].wParam,
                             (PTSTR) (iType ? TEXT (" ") : szKeyName),
                             (TCHAR) (iType ? pmsg[i].wParam : ' '),
                             LOWORD (pmsg[i].lParam),
                             HIWORD (pmsg[i].lParam) & 0xFF,
                             0x01000000 & pmsg[i].lParam ? szYes  : szNo,
                             0x20000000 & pmsg[i].lParam ? szYes  : szNo,
                             0x40000000 & pmsg[i].lParam ? szDown : szUp,
                             0x80000000 & pmsg[i].lParam ? szUp   : szDown)) ;//这里“szMessage [pmsg[i].message - WM_KEYFIRST]”怎么计算？“szFormat [iType]”表示什么？“(TCHAR) (iType ? pmsg[i].wParam : ' ')”如何理解？
          }
          DeleteObject (SelectObject (hdc, GetStockObject (SYSTEM_FONT))) ;
          EndPaint (hwnd, &ps) ;
          return 0 ;

     case WM_DESTROY:
          PostQuitMessage (0) ;
          return 0 ;
     }
     return DefWindowProc (hwnd, message, wParam, lParam) ;
}

这是第6章关于键盘处理的源码，存在理解问题的地方都做了标注，问题积累的有点多，GOOGLE上也找不到对应的解答，望大家帮忙解答下，谢谢！

[ttsping]

DEFAULT_CHARSET默认的字符集 http://msdn.microsoft.com/en-us/library/windows/desktop/dd183499(v=vs.85).aspx 第一个定义的是TCHAR数组 第二个定义的相当于是二维数组。TCHAR数组的数组。 我觉得这个是有些时候没必要“化简”，意思比较直观。 不懂你说的。 http://msdn.microsoft.com/en-us/library/windows/desktop/ms646285(v=vs.85).aspx WM_KEYFIRST你在vs里面f12一下就知道了。 这个你在vs里面看应该不难吧。。