Windows API örnek kodlar

Edit kontrolu (Karakter giriş sınırlı)

Bir Windows API programında, bir Edit kontrolu içinde sadece rakam girişi ile BACKSPACE, DEL, sol ok ve sağ ok tuşlarının devrede olabilmesi için kontrola uygulanan subclassing işlemi fonksiyonunda WM_CHAR mesajına işlem yapabiliriz.

Programın main.c dosyası içeriği aşağıdaki şekilde olacaktır:

main.c

#if defined(UNICODE) && !defined(_UNICODE)
    #define _UNICODE
#elif defined(_UNICODE) && !defined(UNICODE)
    #define UNICODE
#endif

#define _WIN32_WINNT 0x0501
#define _WIN32_IE 0x0501

#include <tchar.h>
#include <windows.h>
#include <commctrl.h>

#define IDC_EDIT 1001

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
/* Subclassing fonksiyon bildirimi */
LRESULT CALLBACK EditRakamProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData);

/*  Make the class name into a global variable  */
TCHAR szClassName[ ] = _T("CodeBlocksWindowsApp");

HWND hwndEdit;

int WINAPI WinMain (HINSTANCE hThisInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpszArgument,
                     int nCmdShow)
{
    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 colour as the background of the window */
    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 */
           _T("Edit (Karakter giriş sınırlı)"), /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           400,                 /* The programs width */
           300,                 /* 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, nCmdShow);

    /* 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)
{
    switch (message)                  /* handle the messages */
    {
         case WM_CREATE:
         {
              // Sadece rakam girilebilen Edit kontrolu
              hwndEdit = CreateWindowEx(0, "EDIT", "",
                             WS_CHILD | WS_VISIBLE | WS_BORDER, 20, 20, 200, 20,
                             hwnd, (HMENU) IDC_EDIT, NULL, NULL);

              SetWindowSubclass(hwndEdit, EditRakamProc, 0, 0);
         }
         break;

         case WM_DESTROY:
             PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
             break;

         default:                       /* for messages that we don't deal with */
             return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

/* Subclassing fonksiyonu */
LRESULT CALLBACK EditRakamProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
  switch (message)
  {
     case WM_CHAR:
     {
        //            0 - 9                   BACKSPACE       Del         Sol ok         Sağ ok
        if ((wParam<48 || wParam>57) && (wParam!=8 && wParam!=127 && wParam!=37 && wParam!=39))  return 0;		
		
        break;
     }
  }
  return DefSubclassProc(hwnd, message, wParam, lParam);
}