23. 领略internet.txt

本书介绍了在Microsoft Windows 98、Microsoft Windows NT 4.0和Windows NT 5.0下程序写作的方法

#include           <windows.h>
        
#include           <wininet.h>
        
#include           <process.h>
        
#include           "resource.h"
        

                  // User-defined messages used in WndProc
        

#define     WM_USER_CHECKFILES    (WM_USER + 1)
        
#define     WM_USER_GETFILES              (WM_USER + 2)
        

                  // Information for FTP download
        

#define     FTPSERVER     TEXT   ("ftp.cpetzold.com")
        
#define     DIRECTORY     TEXT   ("cpetzold.com/ProgWin/UpdDemo")
        
#define     TEMPLATE      TEXT   ("UD??????.TXT")
        

    // Structures used for storing filenames and contents
        
typedef struct
        
{
        
           TCHAR * szFilename ;
        
           char  * szContents ;
        
}
        
FILEINFO ;
        
typedef struct
        
{
        
           int                           iNum ;
        
           FILEINFO              info[1] ;
        
}
        
FILELIST ;
        
    // Structure used for second thread
        
typedef struct
        
{
        
           BOOL bContinue ;
        
           HWND hwnd ;
        
}
        
PARAMS ;
        
                  // Declarations of all functions in program
        
LRESULT     CALLBACK              WndProc (HWND, UINT, WPARAM, LPARAM) ;
        
BOOL               CALLBACK              DlgProc (HWND, UINT, WPARAM, LPARAM) ;
        
VOID                                                      FtpThread (PVOID) ;
        
VOID                                                      ButtonSwitch (HWND, HWND, TCHAR *) ;
        
FILELIST *                                GetFileList (VOID) ;
        
int                                                       Compare (const FILEINFO *, const FILEINFO *) ;
        

                  // A couple globals
        

HINSTANCE hInst ;
        
TCHAR                      szAppName[] = TEXT ("UpdDemo") ;
        

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
        
                                                                PSTR szCmdLine, int iCmdShow)
        
{
        
           HWND                                         hwnd ;
        
           MSG                                          msg ;
        
           WNDCLASS                             wndclass ;
        

           hInst = hInstance ;
        
           wndclass.style                               = 0 ;
        
           wndclass.lpfnWndProc                         = WndProc ;
        
           wndclass.cbClsExtra                          = 0 ;
        
          wndclass.cbWndExtra                          = 0 ;
        
           wndclass.hInstance                           = hInstance ;
        
           wndclass.hIcon                               = LoadIcon (NULL, IDI_APPLICATION) ;
        
           wndclass.hCursor                             = NULL ;
        
           wndclass.hbrBackground               = 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 ("Update Demo with Anonymous FTP"),
        
                      WS_OVERLAPPEDWINDOW | WS_VSCROLL,
        
                      CW_USEDEFAULT, CW_USEDEFAULT,
        
                     CW_USEDEFAULT, CW_USEDEFAULT,
        
                      NULL, NULL, hInstance, NULL) ;
        

           ShowWindow (hwnd, iCmdShow) ;
        
           UpdateWindow (hwnd) ;
        

                  // After window is displayed, check if the latest file exists
        
           SendMessage (hwnd, WM_USER_CHECKFILES, 0, 0) ;
        
           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 FILELIST *     plist ;
        
           static int                                   cxClient, cyClient, cxChar, cyChar ;
        
           HDC                                                         hdc ;
        
           int                                                         i ;
        
           PAINTSTRUCT                                  ps ;
        
           SCROLLINFO                                  si ;
        
           SYSTEMTIME                                   st ;
        
           TCHAR                                                      szFilename [MAX_PATH] ;
        

           switch (message)
        
    {
        
           case   WM_CREATE:
        
                          cxChar = LOWORD (GetDialogBaseUnits ()) ;
        
                          cyChar = HIWORD (GetDialogBaseUnits ()) ;
        
                          return 0 ;
        

           case   WM_SIZE:
        
                          cxClient              = LOWORD (lParam) ;
        
                          cyClient              = HIWORD (lParam) ;
        

                          si.cbSize     = sizeof (SCROLLINFO) ;
        
                          si.fMask              = SIF_RANGE | SIF_PAGE ;
        
                          si.nMin               = 0 ;
        
                          si.nMax               = plist ? plist->iNum - 1 : 0 ;
        
                          si.nPage              = cyClient / cyChar ;
        

                          SetScrollInfo (hwnd, SB_VERT, &si, TRUE) ;
        
                          return 0 ;
        

           case   WM_VSCROLL:
        
                          si.cbSize     = sizeof (SCROLLINFO) ;
        
                          si.fMask              = SIF_POS | SIF_RANGE | SIF_PAGE ;
        
                          GetScrollInfo (hwnd, SB_VERT, &si) ;
        

                          switch (LOWORD (wParam))
        
                          {
        
                          case SB_LINEDOWN: si.nPos += 1 ; break ;
        
                          case SB_LINEUP:   si.nPos -= 1 ; break ;
        
                          case SB_PAGEDOWN: si.nPos += si.nPage ; break ;
        
                          case SB_PAGEUP:   si.nPos -= si.nPage ; break ;
        
                          case SB_THUMBPOSITION: si.nPos = HIWORD (wParam) ;   break ;
        
                          default:                     return 0 ;
        
                          }
        
                          si.fMask = SIF_POS ;
        
                          SetScrollInfo (hwnd, SB_VERT, &si, TRUE) ;
        
                          InvalidateRect (hwnd, NULL, TRUE) ;
        
                          return 0 ;
        

           case   WM_USER_CHECKFILES:
        
                                  // Get the system date & form filename from year and month
        

                          GetSystemTime (&st) ;
        
                          wsprintf (szFilename, TEXT ("UD%04i%02i.TXT"), st.wYear, st.wMonth) ;
        

                                  // Check if the file exists; if so, read all the files
        

                         if (GetFileAttributes (szFilename) != (DWORD) -1)
        
                          {
        
                                         SendMessage (hwnd, WM_USER_GETFILES, 0, 0) ;
        
                                         return 0 ;
        
                          }
        
                                  // Otherwise, get files from Internet.
        
                                  // But first check so we don't try to copy files to a CD-ROM!
        

                          if (GetDriveType (NULL) == DRIVE_CDROM)
        
                          {
        
   MessageBox (hwnd, TEXT ("Cannot run this program from CD-ROM!"),
        
               szAppName, MB_OK | MB_ICONEXCLAMATION) ;
        
                                         return 0 ;
        
                          }
        
                                                 // Ask user if an Internet connection is desired
        

                          if (IDYES == MessageBox (hwnd, TEXT ("Update information from Internet?"),
        
                       szAppName, MB_YESNO | MB_ICONQUESTION))
        

                                                 // Invoke dialog box
        

                          DialogBox (hInst, szAppName, hwnd, DlgProc) ;
        

                                                 // Update display
        

                         SendMessage (hwnd, WM_USER_GETFILES, 0, 0) ;
        
                          return 0 ;
        

           case   WM_USER_GETFILES:
        
                          SetCursor (LoadCursor (NULL, IDC_WAIT)) ;
        
                          ShowCursor (TRUE) ;
        

                                                 // Read in all the disk files
        

                          plist = GetFileList () ;
        

                          ShowCursor (FALSE) ;