Hi Guys
please am studying MFC programming online. part of the tutorial we created a win32 project, then added a .cpp source file to it. below is both files
/* the win32 .cpp file */
// Win32MessagesandEvents.cpp : Defines the entry point for the application.
//
#include "stdafx.h"
#include "Win32MessagesandEvents.h"
#define MAX_LOADSTRING 100
// Global Variables:
HINSTANCE hInst; // current instance
WCHAR szTitle[MAX_LOADSTRING]; // The title bar text
WCHAR szWindowClass[MAX_LOADSTRING]; // the main window class name
// Forward declarations of functions included in this code module:
ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK About(HWND, UINT, WPARAM, LPARAM);
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPWSTR lpCmdLine,
_In_ int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
// TODO: Place code here.
// Initialize global strings
LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadStringW(hInstance, IDC_WIN32MESSAGESANDEVENTS, szWindowClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);
// Perform application initialization:
if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}
HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_WIN32MESSAGESANDEVENTS));
MSG msg;
// Main message loop:
while (GetMessage(&msg, nullptr, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
return (int) msg.wParam;
}
//
// FUNCTION: MyRegisterClass()
//
// PURPOSE: Registers the window class.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEXW wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WIN32MESSAGESANDEVENTS));
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = MAKEINTRESOURCEW(IDC_WIN32MESSAGESANDEVENTS);
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassExW(&wcex);
}
//
// FUNCTION: InitInstance(HINSTANCE, 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)
{
hInst = hInstance; // Store instance handle in our global variable
HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);
if (!hWnd)
{
return FALSE;
}
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
return TRUE;
}
//
// FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
// 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
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_COMMAND:
{
int wmId = LOWORD(wParam);
// Parse the menu selections:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code that uses hdc here...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
// Message handler for about box.
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
UNREFERENCED_PARAMETER(lParam);
switch (message)
{
case WM_INITDIALOG:
return (INT_PTR)TRUE;
case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return (INT_PTR)TRUE;
}
break;
}
return (INT_PTR)FALSE;
}
/* the added .cpp file */
#include "stdafx.h"
#include <afxwin.h>
class CMainFrame : public CFrameWnd {
public:
CMainFrame();
protected:
afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct);
DECLARE_MESSAGE_MAP()
};
CMainFrame::CMainFrame() {
// Create the window's frame
Create(NULL, L"MFC Messages Demo", WS_OVERLAPPEDWINDOW,
CRect(120, 100, 700, 480), NULL);
}
class CMessagesApp : public CWinApp {
public:
BOOL InitInstance();
};
BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd)
ON_WM_CREATE()
END_MESSAGE_MAP()
int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct) {
// Call the base class to create the window
if (CFrameWnd::OnCreate(lpCreateStruct) == 0) {
// If the window was successfully created, let the user know
MessageBox(L"The window has been created!!!");
// Since the window was successfully created, return 0
return 0;
}
// Otherwise, return -1
return -1;
}
BOOL CMessagesApp::InitInstance() {
m_pMainWnd = new CMainFrame;
m_pMainWnd->ShowWindow(SW_SHOW);
m_pMainWnd->UpdateWindow();
return TRUE;
}
CMessagesApp theApp;
when i compile the above project, i get this error messages
Severity Code
Description Project
File Line
Suppression State
Error (active) #error directive: WINDOWS.H already included. MFC apps must not #include <windows.h>
Win32MessagesandEvents c:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\atlmfc\include\afxv_w32.h
16
Severity Code
Description Project
File Line
Suppression State
Error C1189
#error: WINDOWS.H already included. MFC apps must not #include <windows.h>
Win32MessagesandEvents c:\program files (x86)\microsoft visual studio 14.0\vc\atlmfc\include\afxv_w32.h
16
i have tried everything i think i can try. can someone be of help
