Code Explanation: Wizard-Generated Code in Visual C++ Device Projects

Article
09/03/2015

Visual C++ capabilities and wizards simplify most of the mundane tasks of generating multiplatform device applications, configuration files, and project files. This walkthrough describes the code automatically generated for you by the Windows 32 Device Application Wizard. That way, you can extend and modify Windows applications to suit your needs.

Wizard-Generated Code for a Windows 32 Device Application

If you are familiar with Windows (win32) desktop programming, you can easily spot the main routines generated for you by the wizard.

In a typical Windows device application, the main entry is located in the <yourprojectname>.cpp file. A sample listing of this file follows.

At a quick glance, the application has the following main functionality:

WinMain function
MyRegisterClass function
InitInstance function
An About Dialog function

Each of these functions is illustrated in the following examples:

WinMain function: int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow). For more information, see WinMain Function.

int WINAPI WinMain(HINSTANCE hInstance,
                HINSTANCE hPrevInstance,
                LPTSTR    lpCmdLine,
                int       nCmdShow)
{
      MSG msg;

      // Perform application initialization:
      if (!InitInstance(hInstance, nCmdShow)) 
      {
            return FALSE;
      }

Win32 Platforms. For more information, see Windows Platforms (CRT).

#ifndef WIN32_PLATFORM_WFSP
        HACCEL hAccelTable;
        hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_WIN32SMARTDEVICE);
#endif // !WIN32_PLATFORM_WFSP

Message loops. For more information, see Message Handling and Command Targets.

        // Main message loop:
        while (GetMessage(&msg, NULL, 0, 0)) 
        {
#ifndef WIN32_PLATFORM_WFSP
            if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)) 
#endif // !WIN32_PLATFORM_WFSP
            {
                  TranslateMessage(&msg);
                  DispatchMessage(&msg);
            }
      }

      return (int) msg.wParam;
}

The MyRegisterClass function registers the window application.

//  FUNCTION: MyRegisterClass()
ATOM MyRegisterClass(HINSTANCE hInstance, LPTSTR szWindowClass)
{
      WNDCLASS wc;

      wc.style         = CS_HREDRAW | CS_VREDRAW;
      wc.lpfnWndProc   = (WNDPROC)WndProc;
      wc.cbClsExtra    = 0;
      wc.cbWndExtra    = 0;
      wc.hInstance     = hInstance;
      wc.hIcon         = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WIN32SMARTDEVICE));
      wc.hCursor       = 0;
      wc.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
      wc.lpszMenuName  = 0;
      wc.lpszClassName = szWindowClass;

      return RegisterClass(&wc);
}

InitInstance: FUNCTION InitInstance(HANDLE, int) For more information, see InitInstance Member Function.

WIN32_PLATFORM_WFSP is used as a condition for Smartphone and WIN32_PLATFORM_PSPC for Pocket PC. You can always define your own conditionals if you want to additionally differentiate.

// FUNCTION: InitInstance(HANDLE, int)
// PURPOSE: Saves instance handle and creates main window.
// COMMENTS:
// In this function, we save the instance handle in a global 
// variable and create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
    HWND hWnd;
    TCHAR szTitle[MAX_LOADSTRING];        
// title bar text
    TCHAR szWindowClass[MAX_LOADSTRING];  
// main window class name

    g_hInst = hInstance; 
// Store instance handle in your global variable.

#ifdef WIN32_PLATFORM_PSPC
    // SHInitExtraControls should be called once during your application's initialization to initialize any
    // of the Pocket PC special controls such as CAPEDIT and SIPPREF.
    SHInitExtraControls();
#endif // WIN32_PLATFORM_PSPC

    LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING); 
    LoadString(hInstance, IDC_WIN32SMARTDEVICE, szWindowClass, MAX_LOADSTRING);

#if defined(WIN32_PLATFORM_PSPC) || defined(WIN32_PLATFORM_WFSP)
    //If it is already running, then focus on the window, and exit.
    hWnd = FindWindow(szWindowClass, szTitle);  
    if (hWnd) 
    {
        // Set the focus to the foremost child window.
        // The "| 0x00000001" is used to bring any owned windows
        //to the foreground and activate them.
        SetForegroundWindow((HWND)((ULONG) hWnd | 0x00000001));
        return 0;
    } 
#endif // WIN32_PLATFORM_PSPC || WIN32_PLATFORM_WFSP

    if (!MyRegisterClass(hInstance, szWindowClass))
    {
      return FALSE;
    }

    hWnd = CreateWindow(szWindowClass, szTitle, WS_VISIBLE,
        CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL);

    if (!hWnd)
    {
        return FALSE;
    }

#ifdef WIN32_PLATFORM_PSPC
    // When the main window is created using CW_USEDEFAULT, 
    // the height of the menubar is not taken into account. 
    // So the generated code resizes the window after creating it.
    if (g_hWndMenuBar)
    {
        RECT rc;
        RECT rcMenuBar;

        GetWindowRect(hWnd, &rc);
        GetWindowRect(g_hWndMenuBar, &rcMenuBar);
        rc.bottom -= (rcMenuBar.bottom - rcMenuBar.top);

        MoveWindow(hWnd, rc.left, rc.top, rc.right-rc.left, rc.bottom-rc.top, FALSE);
    }
#endif // WIN32_PLATFORM_PSPC

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);


    return TRUE;
}

An About dialog box is also generated for your application as an example of how to build other dialog boxes you may want: LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)

// win32smartdevice.cpp : Defines the entry point for the application.
#include "stdafx.h"
#include "win32smartdevice.h"
#include <windows.h>
#include <commctrl.h>

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE               g_hInst;                
// Current instance:
HWND                    g_hWndMenuBar;          
// Menu bar handle

// Forward declarations of functions included in this code module:
ATOM              MyRegisterClass(HINSTANCE, LPTSTR);
BOOL              InitInstance(HINSTANCE, int);
LRESULT CALLBACK  WndProc(HWND, UINT, WPARAM, LPARAM);
#ifndef WIN32_PLATFORM_WFSP
LRESULT CALLBACK  About(HWND, UINT, WPARAM, LPARAM);
#endif 
// !WIN32_PLATFORM_WFSP
//  FUNCTION: WndProc(HWND, unsigned, WORD, LONG)
//  PURPOSE:  Processes messages for the main window.
//  WM_COMMAND    - process the application menu
//  WM_PAINT      - Paint the main window
//  WM_DESTROY    - post a quit message and return

Some of the main messages, such as WM_COMMAND are already included for you and for extensibility. WinProc is included for a processing system and user input messages: LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam. For more information about WinProc, see Windows Overview.

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;
        HGDIOBJ  hbrWhite, hbrGray; 
        POINT aptStar[6] = {50,2, 2,98, 98,33, 2,33, 98,98, 50,2}; 

#if defined(SHELL_AYGSHELL) && !defined(WIN32_PLATFORM_WFSP)
    static SHACTIVATEINFO s_sai;
#endif // SHELL_AYGSHELL && !WIN32_PLATFORM_WFSP
    switch (message) 
    {
        case WM_COMMAND:
            wmId    = LOWORD(wParam); 
            wmEvent = HIWORD(wParam); 
            // Parse the menu selections:
            switch (wmId)
            {
#ifndef WIN32_PLATFORM_WFSP
                case IDM_HELP_ABOUT:
                    DialogBox(g_hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
                    break;
#endif // !WIN32_PLATFORM_WFSP
#ifdef WIN32_PLATFORM_WFSP
                case IDM_OK:
                    DestroyWindow(hWnd);
                    break;
#endif // WIN32_PLATFORM_WFSP
#ifndef WIN32_PLATFORM_WFSP
                case IDM_OK:
                    SendMessage (hWnd, WM_CLOSE, 0, 0);                       
                    break;
#endif // !WIN32_PLATFORM_WFSP
                default:
                    return DefWindowProc(hWnd, message, wParam, lParam);
            }
            break;
        case WM_CREATE:
#ifdef SHELL_AYGSHELL
            SHMENUBARINFO mbi;

            memset(&mbi, 0, sizeof(SHMENUBARINFO));
            mbi.cbSize     = sizeof(SHMENUBARINFO);
            mbi.hwndParent = hWnd;
            mbi.nToolBarId = IDR_MENU;
            mbi.hInstRes   = g_hInst;

            if (!SHCreateMenuBar(&mbi)) 
            {
                g_hWndMenuBar = NULL;
            }
            else
            {
                g_hWndMenuBar = mbi.hwndMB;
            }

#ifndef WIN32_PLATFORM_WFSP
            // Initialize the shell activate info structure
            memset(&s_sai, 0, sizeof (s_sai));
            s_sai.cbSize = sizeof (s_sai);
#endif // !WIN32_PLATFORM_WFSP
#endif // SHELL_AYGSHELL
      hbrWhite = GetStockObject(WHITE_BRUSH); 
        hbrGray  = GetStockObject(GRAY_BRUSH); 
        return 0L; 
break;
        case WM_PAINT:
         RECT  rc;
       hdc = BeginPaint(hWnd, &ps); 
       GetClientRect(hWnd, &rc); 
       Polyline(hdc, aptStar, 6); 
       EndPaint(hWnd, &ps); 
       return 0L; 

            break;
        case WM_DESTROY:
#ifdef SHELL_AYGSHELL
            CommandBar_Destroy(g_hWndMenuBar);
#endif // SHELL_AYGSHELL
            PostQuitMessage(0);
            break;

#if defined(SHELL_AYGSHELL) && !defined(WIN32_PLATFORM_WFSP)
        case WM_ACTIVATE:
            // Notify shell of your activate message.
            SHHandleWMActivate(hWnd, wParam, lParam, &s_sai, FALSE);
            break;
        case WM_SETTINGCHANGE:
            SHHandleWMSettingChange(hWnd, wParam, lParam, &s_sai);
            break;
#endif // SHELL_AYGSHELL && !WIN32_PLATFORM_WFSP

        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

#ifndef WIN32_PLATFORM_WFSP
// Message handler for about box.
LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
        case WM_INITDIALOG:
#ifdef SHELL_AYGSHELL
            {
                // Create a Done button and size it.  
                SHINITDLGINFO shidi;
                shidi.dwMask = SHIDIM_FLAGS;
                shidi.dwFlags = SHIDIF_DONEBUTTON | SHIDIF_SIPDOWN | SHIDIF_SIZEDLGFULLSCREEN | SHIDIF_EMPTYMENU;
                shidi.hDlg = hDlg;
                SHInitDialog(&shidi);
            }
#endif // SHELL_AYGSHELL

            return TRUE;

        case WM_COMMAND:
#ifdef SHELL_AYGSHELL
            if (LOWORD(wParam) == IDOK)
#endif
            {
                EndDialog(hDlg, LOWORD(wParam));
                return TRUE;
            }
            break;

        case WM_CLOSE:
            EndDialog(hDlg, message);
            return TRUE;

#ifdef _DEVICE_RESOLUTION_AWARE
        case WM_SIZE:
            {
            DRA::RelayoutDialog(
                  g_hInst, 
                  hDlg, 
                  DRA::GetDisplayMode() != DRA::Portrait ? MAKEINTRESOURCE(IDD_ABOUTBOX_WIDE) : MAKEINTRESOURCE(IDD_ABOUTBOX));
            }
            break;
#endif
    }
    return FALSE;
}
#endif // !WIN32_PLATFORM_WFSP

Code Explanation: Wizard-Generated Code in Visual C++ Device Projects

Wizard-Generated Code for a Windows 32 Device Application

See Also

Reference

Other Resources

Additional resources