// Multi document interface demo
#define IDI_ICON 101
#define IDC_CHILD_EDIT 200
#define IDM_FILE_EXIT 1000
#define IDM_FILE_NEW 1001
#define ID_MDI_CLIENT 1002
#define ID_MDI_FIRSTCHILD 1003
#include <windows.h>
const TCHAR ClassName[] = TEXT("MainWindowClass");
const TCHAR ChildClassName[] =TEXT( "ChildWindowClass");
HWND static hWndClient;
//HWND static mhWnd;

LRESULT CALLBACK ChildProc( HWND hWnd,UINT Msg,WPARAM wParam,LPARAM lParam )
{
switch(Msg)// Handle messages from the child windows
{
case WM_CREATE:
{
HWND hEdit;
// Create Edit Control
hEdit = CreateWindowEx(WS_EX_CLIENTEDGE,TEXT("EDIT"),TEXT( ""),
WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_HSCROLL | ES_MULTILINE | ES_AUTOVSCROLL | ES_AUTOHSCROLL,
0, 0, 100, 100, hWnd, (HMENU)IDC_CHILD_EDIT, GetModuleHandle(NULL), NULL);
if(hEdit == NULL)
MessageBox(hWnd, TEXT("Could not create edit box."),TEXT( "Error"), MB_OK | MB_ICONERROR);
}
break;
case WM_MDIACTIVATE:
{
//place code for execution prior to activation
}
case WM_SIZE:
{
HWND hEdit;
RECT rcClient;
GetClientRect(hWnd, &rcClient);
hEdit = GetDlgItem(hWnd, IDC_CHILD_EDIT);
SetWindowPos(hEdit, NULL, 0, 0, rcClient.right, rcClient.bottom, SWP_NOZORDER);
}
return DefMDIChildProc(hWnd, Msg, wParam, lParam);
break;
}
return DefMDIChildProc(hWnd, Msg, wParam, lParam);
}

LRESULT CALLBACK WndProc( HWND hWnd,UINT Msg,WPARAM wParam,LPARAM lParam )
{
switch (Msg)
//main window message loop
{
case WM_CREATE:
{
HMENU hMenubar;
HMENU hMenu;
hMenubar = CreateMenu();
hMenu = CreateMenu();
AppendMenu(hMenu, MF_STRING, IDM_FILE_NEW, TEXT("New"));
AppendMenu(hMenu, MF_STRING, IDM_FILE_EXIT , TEXT("Quit"));
AppendMenu(hMenubar, MF_POPUP, (UINT_PTR)hMenu,TEXT("&File"));
SetMenu(hWnd, hMenubar);
CLIENTCREATESTRUCT ccs;
ccs.hWindowMenu = GetSubMenu(GetMenu(hWnd), 0);
ccs.idFirstChild = ID_MDI_FIRSTCHILD;
hWndClient = CreateWindowEx(WS_EX_CLIENTEDGE, TEXT("MDICLIENT"), NULL,WS_CHILD | WS_CLIPCHILDREN | WS_VSCROLL | WS_HSCROLL,CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,hWnd, (HMENU)ID_MDI_CLIENT, (HINSTANCE)GetWindowLong(hWnd, GWL_HINSTANCE), (LPVOID)&ccs);
if(!hWndClient)
{
MessageBox(hWnd, TEXT("Failed To Create The Client Window"),TEXT("Error"), MB_OK);
}
ShowWindow(hWndClient, SW_SHOW);
}
break;

case WM_COMMAND:
{
switch(LOWORD(wParam))
{
//create new child window
case IDM_FILE_NEW:
{
HWND hChild;
CREATESTRUCT cs;
ZeroMemory(&cs, sizeof(CREATESTRUCT));
hChild = CreateWindowEx(WS_EX_MDICHILD,ChildClassName,TEXT("Child Window"),WS_CHILD | WS_VISIBLE | WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,hWndClient,NULL,(HINSTANCE)GetWindowLong(hWnd, GWL_HINSTANCE),&cs);
if(!hChild)
MessageBox(hWnd, TEXT("Failed To Create The Child Window"),TEXT( "Error"), MB_OK);
}
break;
//exit application
case IDM_FILE_EXIT:
PostMessage(hWnd, WM_CLOSE, 0, 0);
break;
default:
{
if(LOWORD(wParam) >= ID_MDI_FIRSTCHILD)
DefFrameProc(hWnd, hWndClient, Msg, wParam, lParam);
else
{
HWND hChild;
hChild = (HWND)SendMessage(hWndClient, WM_MDIGETACTIVE,0,0);
if(hChild)
SendMessage(hChild, WM_COMMAND, wParam, lParam);
}
}
}
return 0;
}
break;
case WM_CLOSE:
DestroyWindow(hWnd);
break;

case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefFrameProc(hWnd, hWndClient, Msg, wParam, lParam);
}
return 0;
}
//winmain for main window
INT WINAPI WinMain( HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,INT nCmdShow )
{
WNDCLASSEX wc;
wc.cbSize = sizeof(WNDCLASSEX);
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_ICON));
wc.hIconSm = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON));
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = NULL;
wc.lpszClassName = ClassName;
if (!RegisterClassEx(&wc))
{
MessageBox(NULL, TEXT("Failed To Register The Window Class."),TEXT("Error"), MB_OK | MB_ICONERROR);
return 0;
}
//winmain for child window
wc.lpfnWndProc = (WNDPROC)ChildProc;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_3DSHADOW + 1);
wc.lpszMenuName = NULL;
wc.lpszClassName = ChildClassName;

if(!RegisterClassEx(&wc))
{
MessageBox(NULL,TEXT("Failed To Register The Child Window Class"),TEXT("Error"), MB_OK | MB_ICONERROR);
return 0;
}
HWND hWnd;
hWnd = CreateWindowEx(WS_EX_CLIENTEDGE,ClassName,TEXT("MDI"),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,600,400,NULL,NULL,hInstance,NULL);
if (!hWnd)
{
MessageBox(NULL, TEXT("Window Creation Failed."), TEXT("Error"), MB_OK | MB_ICONERROR);
return 0;
}
ShowWindow(hWnd, SW_SHOW);
UpdateWindow(hWnd);
MSG Msg;
while (GetMessage(&Msg, NULL, 0, 0))
{
if (!TranslateMDISysAccel(hWndClient, &Msg))
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
}
return Msg.wParam;
}