mdi.c

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/*
  Thanks to theForger from winprog.org
*/
#include <windows.h>
#include <commctrl.h>

#include <string.h>
#include "resource.h"

const char g_szClassName[] = "myWindowClass";
const char g_szChildClassName[] = "myMDIChildWindowClass";

#define IDC_MAIN_MDI    101
#define IDC_MAIN_TOOL   102
#define IDC_MAIN_STATUS 103

#define IDC_CHILD_EDIT  101

#define ID_MDI_FIRSTCHILD 50000

HWND g_hMDIClient = NULL;
HWND g_hMainWindow = NULL;

BOOL LoadTextFileToEdit(HWND hEdit, LPCTSTR pszFileName)
{
    HANDLE hFile;
    BOOL bSuccess = FALSE;

    hFile = CreateFile(pszFileName, GENERIC_READ, FILE_SHARE_READ, NULL,
        OPEN_EXISTING, 0, NULL);
    if(hFile != INVALID_HANDLE_VALUE)
    {
        DWORD dwFileSize;

        dwFileSize = GetFileSize(hFile, NULL);
        if(dwFileSize != 0xFFFFFFFF)
        {
            LPSTR pszFileText;

            pszFileText = GlobalAlloc(GPTR, dwFileSize + 1);
            if(pszFileText != NULL)
            {
                DWORD dwRead;

                if(ReadFile(hFile, pszFileText, dwFileSize, &dwRead, NULL))
                {
                    pszFileText[dwFileSize] = 0; // Add null terminator
                    if(SetWindowText(hEdit, pszFileText))
                        bSuccess = TRUE; // It worked!
                }
                GlobalFree(pszFileText);
            }
        }
        CloseHandle(hFile);
    }
    return bSuccess;
}

BOOL SaveTextFileFromEdit(HWND hEdit, LPCTSTR pszFileName)
{
    HANDLE hFile;
    BOOL bSuccess = FALSE;

    hFile = CreateFile(pszFileName, GENERIC_WRITE, 0, NULL,
        CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if(hFile != INVALID_HANDLE_VALUE)
    {
        DWORD dwTextLength;

        dwTextLength = GetWindowTextLength(hEdit);
        // No need to bother if there's no text.
        if(dwTextLength > 0)
        {
            LPSTR pszText;
            DWORD dwBufferSize = dwTextLength + 1;

            pszText = GlobalAlloc(GPTR, dwBufferSize);
            if(pszText != NULL)
            {
                if(GetWindowText(hEdit, pszText, dwBufferSize))
                {
                    DWORD dwWritten;

                    if(WriteFile(hFile, pszText, dwTextLength, &dwWritten, NULL))
                        bSuccess = TRUE;
                }
                GlobalFree(pszText);
            }
        }
        CloseHandle(hFile);
    }
    return bSuccess;
}

void DoFileOpen(HWND hwnd)
{
    OPENFILENAME ofn;
    char szFileName[MAX_PATH] = "";

    ZeroMemory(&ofn, sizeof(ofn));

    ofn.lStructSize = sizeof(ofn);
    ofn.hwndOwner = hwnd;
    ofn.lpstrFilter = "Text Files (*.txt)\0*.txt\0All Files (*.*)\0*.*\0";
    ofn.lpstrFile = szFileName;
    ofn.nMaxFile = MAX_PATH;
    ofn.Flags = OFN_EXPLORER | OFN_FILEMUSTEXIST | OFN_HIDEREADONLY;
    ofn.lpstrDefExt = "txt";

    if(GetOpenFileName(&ofn))
    {
        HWND hEdit = GetDlgItem(hwnd, IDC_CHILD_EDIT);
        if(LoadTextFileToEdit(hEdit, szFileName))
        {
            SendDlgItemMessage(g_hMainWindow, IDC_MAIN_STATUS, SB_SETTEXT, 0, (LPARAM)"Opened...");
            SendDlgItemMessage(g_hMainWindow, IDC_MAIN_STATUS, SB_SETTEXT, 1, (LPARAM)szFileName);

            SetWindowText(hwnd, szFileName);
        }
    }
}

void DoFileSave(HWND hwnd)
{
    OPENFILENAME ofn;
    char szFileName[MAX_PATH] = "";

    ZeroMemory(&ofn, sizeof(ofn));

    ofn.lStructSize = sizeof(ofn);
    ofn.hwndOwner = hwnd;
    ofn.lpstrFilter = "Text Files (*.txt)\0*.txt\0All Files (*.*)\0*.*\0";
    ofn.lpstrFile = szFileName;
    ofn.nMaxFile = MAX_PATH;
    ofn.lpstrDefExt = "txt";
    ofn.Flags = OFN_EXPLORER | OFN_PATHMUSTEXIST | OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT;

    if(GetSaveFileName(&ofn))
    {
        HWND hEdit = GetDlgItem(hwnd, IDC_CHILD_EDIT);
        if(SaveTextFileFromEdit(hEdit, szFileName))
        {
            SendDlgItemMessage(g_hMainWindow, IDC_MAIN_STATUS, SB_SETTEXT, 0, (LPARAM)"Saved...");
            SendDlgItemMessage(g_hMainWindow, IDC_MAIN_STATUS, SB_SETTEXT, 1, (LPARAM)szFileName);

            SetWindowText(hwnd, szFileName);
        }
    }
}

HWND CreateNewMDIChild(HWND hMDIClient)
{
    MDICREATESTRUCT mcs;
    HWND hChild;

    mcs.szTitle = "[Untitled]";
    mcs.szClass = g_szChildClassName;
    mcs.hOwner  = GetModuleHandle(NULL);
    mcs.x = mcs.cx = CW_USEDEFAULT;
    mcs.y = mcs.cy = CW_USEDEFAULT;
    mcs.style = MDIS_ALLCHILDSTYLES;

    hChild = (HWND)SendMessage(hMDIClient, WM_MDICREATE, 0, (LPARAM)&mcs);
    if(!hChild)
    {
        MessageBox(hMDIClient, "MDI Child creation failed.", "Oh Oh...",
            MB_ICONEXCLAMATION | MB_OK);
    }
    return hChild;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
        case WM_CREATE:
        {
            HWND hTool;
            TBBUTTON tbb[3];
            TBADDBITMAP tbab;

            HWND hStatus;
            int statwidths[] = {100, -1};

            CLIENTCREATESTRUCT ccs;

            // Create MDI Client

            // Find window menu where children will be listed
            ccs.hWindowMenu  = GetSubMenu(GetMenu(hwnd), 2);
            ccs.idFirstChild = ID_MDI_FIRSTCHILD;

            g_hMDIClient = CreateWindowEx(WS_EX_CLIENTEDGE, "mdiclient", NULL,
                WS_CHILD | WS_CLIPCHILDREN | WS_VSCROLL | WS_HSCROLL | WS_VISIBLE,
                CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
                hwnd, (HMENU)IDC_MAIN_MDI, GetModuleHandle(NULL), (LPVOID)&ccs);

            if(g_hMDIClient == NULL)
                MessageBox(hwnd, "Could not create MDI client.", "Error", MB_OK | MB_ICONERROR);

            // Create Toolbar

            hTool = CreateWindowEx(0, TOOLBARCLASSNAME, NULL, WS_CHILD | WS_VISIBLE, 0, 0, 0, 0,
                hwnd, (HMENU)IDC_MAIN_TOOL, GetModuleHandle(NULL), NULL);
            if(hTool == NULL)
                MessageBox(hwnd, "Could not create tool bar.", "Error", MB_OK | MB_ICONERROR);

            // Send the TB_BUTTONSTRUCTSIZE message, which is required for
            // backward compatibility.
            SendMessage(hTool, TB_BUTTONSTRUCTSIZE, (WPARAM)sizeof(TBBUTTON), 0);

            tbab.hInst = HINST_COMMCTRL;
            tbab.nID = IDB_STD_SMALL_COLOR;
            SendMessage(hTool, TB_ADDBITMAP, 0, (LPARAM)&tbab);

            ZeroMemory(tbb, sizeof(tbb));
            tbb[0].iBitmap = STD_FILENEW;
            tbb[0].fsState = TBSTATE_ENABLED;
            tbb[0].fsStyle = TBSTYLE_BUTTON;
            tbb[0].idCommand = ID_FILE_NEW;

            tbb[1].iBitmap = STD_FILEOPEN;
            tbb[1].fsState = TBSTATE_ENABLED;
            tbb[1].fsStyle = TBSTYLE_BUTTON;
            tbb[1].idCommand = ID_FILE_OPEN;

            tbb[2].iBitmap = STD_FILESAVE;
            tbb[2].fsState = TBSTATE_ENABLED;
            tbb[2].fsStyle = TBSTYLE_BUTTON;
            tbb[2].idCommand = ID_FILE_SAVEAS;

            SendMessage(hTool, TB_ADDBUTTONS, sizeof(tbb)/sizeof(TBBUTTON), (LPARAM)&tbb);

            // Create Status bar

            hStatus = CreateWindowEx(0, STATUSCLASSNAME, NULL,
                WS_CHILD | WS_VISIBLE | SBARS_SIZEGRIP, 0, 0, 0, 0,
                hwnd, (HMENU)IDC_MAIN_STATUS, GetModuleHandle(NULL), NULL);

            SendMessage(hStatus, SB_SETPARTS, sizeof(statwidths)/sizeof(int), (LPARAM)statwidths);
            SendMessage(hStatus, SB_SETTEXT, 0, (LPARAM)"Hi there :)");
        }
        break;
        case WM_SIZE:
        {
            HWND hTool;
            RECT rcTool;
            int iToolHeight;

            HWND hStatus;
            RECT rcStatus;
            int iStatusHeight;

            HWND hMDI;
            int iMDIHeight;
            RECT rcClient;

            // Size toolbar and get height

            hTool = GetDlgItem(hwnd, IDC_MAIN_TOOL);
            SendMessage(hTool, TB_AUTOSIZE, 0, 0);

            GetWindowRect(hTool, &rcTool);
            iToolHeight = rcTool.bottom - rcTool.top;

            // Size status bar and get height

            hStatus = GetDlgItem(hwnd, IDC_MAIN_STATUS);
            SendMessage(hStatus, WM_SIZE, 0, 0);

            GetWindowRect(hStatus, &rcStatus);
            iStatusHeight = rcStatus.bottom - rcStatus.top;

            // Calculate remaining height and size edit

            GetClientRect(hwnd, &rcClient);

            iMDIHeight = rcClient.bottom - iToolHeight - iStatusHeight;

            hMDI = GetDlgItem(hwnd, IDC_MAIN_MDI);
            SetWindowPos(hMDI, NULL, 0, iToolHeight, rcClient.right, iMDIHeight, SWP_NOZORDER);
        }
        break;
        case WM_CLOSE:
            DestroyWindow(hwnd);
        break;
        case WM_DESTROY:
            PostQuitMessage(0);
        break;
        case WM_COMMAND:
            switch(LOWORD(wParam))
            {
                case ID_FILE_EXIT:
                    PostMessage(hwnd, WM_CLOSE, 0, 0);
                break;
                case ID_FILE_NEW:
                    CreateNewMDIChild(g_hMDIClient);
                break;
                case ID_FILE_OPEN:
                {
                    HWND hChild = CreateNewMDIChild(g_hMDIClient);
                    if(hChild)
                    {
                        DoFileOpen(hChild);
                    }
                }
                break;
                case ID_FILE_CLOSE:
                {
                    HWND hChild = (HWND)SendMessage(g_hMDIClient, WM_MDIGETACTIVE,0,0);
                    if(hChild)
                    {
                        SendMessage(hChild, WM_CLOSE, 0, 0);
                    }
                }
                break;
                case ID_WINDOW_TILE:
                    SendMessage(g_hMDIClient, WM_MDITILE, 0, 0);
                break;
                case ID_WINDOW_CASCADE:
                    SendMessage(g_hMDIClient, WM_MDICASCADE, 0, 0);
                break;
                default:
                {
                    if(LOWORD(wParam) >= ID_MDI_FIRSTCHILD)
                    {
                        DefFrameProc(hwnd, g_hMDIClient, WM_COMMAND, wParam, lParam);
                    }
                    else
                    {
                        HWND hChild = (HWND)SendMessage(g_hMDIClient, WM_MDIGETACTIVE,0,0);
                        if(hChild)
                        {
                            SendMessage(hChild, WM_COMMAND, wParam, lParam);
                        }
                    }
                }
            }
        break;
        default:
            return DefFrameProc(hwnd, g_hMDIClient, msg, wParam, lParam);
    }
    return 0;
}

LRESULT CALLBACK MDIChildWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch(msg)
    {
        case WM_CREATE:
        {
            HFONT hfDefault;
            HWND hEdit;

            // Create Edit Control

            hEdit = CreateWindowEx(WS_EX_CLIENTEDGE, "EDIT", "",
                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, "Could not create edit box.", "Error", MB_OK | MB_ICONERROR);

            hfDefault = GetStockObject(DEFAULT_GUI_FONT);
            SendMessage(hEdit, WM_SETFONT, (WPARAM)hfDefault, MAKELPARAM(FALSE, 0));
        }
        break;
        case WM_MDIACTIVATE:
        {
            HMENU hMenu, hFileMenu;
            UINT EnableFlag;

            hMenu = GetMenu(g_hMainWindow);
            if(hwnd == (HWND)lParam)
            {      //being activated, enable the menus
                EnableFlag = MF_ENABLED;
            }
            else
            {                          //being de-activated, gray the menus
                EnableFlag = MF_GRAYED;
            }

            EnableMenuItem(hMenu, 1, MF_BYPOSITION | EnableFlag);
            EnableMenuItem(hMenu, 2, MF_BYPOSITION | EnableFlag);

            hFileMenu = GetSubMenu(hMenu, 0);
            EnableMenuItem(hFileMenu, ID_FILE_SAVEAS, MF_BYCOMMAND | EnableFlag);

            EnableMenuItem(hFileMenu, ID_FILE_CLOSE, MF_BYCOMMAND | EnableFlag);
            EnableMenuItem(hFileMenu, ID_FILE_CLOSEALL, MF_BYCOMMAND | EnableFlag);

            DrawMenuBar(g_hMainWindow);
        }
        break;
        case WM_COMMAND:
            switch(LOWORD(wParam))
            {
                case ID_FILE_OPEN:
                    DoFileOpen(hwnd);
                break;
                case ID_FILE_SAVEAS:
                    DoFileSave(hwnd);
                break;
                case ID_EDIT_CUT:
                    SendDlgItemMessage(hwnd, IDC_CHILD_EDIT, WM_CUT, 0, 0);
                break;
                case ID_EDIT_COPY:
                    SendDlgItemMessage(hwnd, IDC_CHILD_EDIT, WM_COPY, 0, 0);
                break;
                case ID_EDIT_PASTE:
                    SendDlgItemMessage(hwnd, IDC_CHILD_EDIT, WM_PASTE, 0, 0);
                break;
            }
        break;
        case WM_SIZE:
        {
            HWND hEdit;
            RECT rcClient;

            // Calculate remaining height and size edit

            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);
        default:
            return DefMDIChildProc(hwnd, msg, wParam, lParam);

    }
    return 0;
}

BOOL SetUpMDIChildWindowClass(HINSTANCE hInstance)
{
    WNDCLASSEX wc;

    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.style         = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc   = MDIChildWndProc;
    wc.cbClsExtra    = 0;
    wc.cbWndExtra    = 0;
    wc.hInstance     = hInstance;
    wc.hIcon         = LoadIcon(NULL, (LPCTSTR)IDI_APPLICATION);
    wc.hCursor       = LoadCursor(NULL, (LPCTSTR)IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_3DFACE+1);
    wc.lpszMenuName  = NULL;
    wc.lpszClassName = g_szChildClassName;
    wc.hIconSm       = LoadIcon(NULL, (LPCTSTR)IDI_APPLICATION);

    if(!RegisterClassEx(&wc))
    {
        MessageBox(0, "Could Not Register Child Window", "Oh Oh...",
            MB_ICONEXCLAMATION | MB_OK);
        return FALSE;
    }
    else
        return TRUE;
}


int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASSEX wc;
    HWND hwnd;
    MSG Msg;

    InitCommonControls();

    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.style         = 0;
    wc.lpfnWndProc   = WndProc;
    wc.cbClsExtra    = 0;
    wc.cbWndExtra    = 0;
    wc.hInstance     = hInstance;
    wc.hIcon         = LoadIcon(NULL, (LPCTSTR)IDI_APPLICATION);
    wc.hCursor       = LoadCursor(NULL, (LPCTSTR)IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    wc.lpszMenuName  = MAKEINTRESOURCE(IDR_MAINMENU);
    wc.lpszClassName = g_szClassName;
    wc.hIconSm       = LoadIcon(NULL, (LPCTSTR)IDI_APPLICATION);

    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    if(!SetUpMDIChildWindowClass(hInstance))
        return 0;

    hwnd = CreateWindowEx(
        0,
        g_szClassName,
        "MDI Test Application",
        WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN,
        CW_USEDEFAULT, CW_USEDEFAULT, 480, 320,
        NULL, NULL, hInstance, NULL);

    if(hwnd == NULL)
    {
        MessageBox(NULL, "Window Creation Failed!", "Error!",
            MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    g_hMainWindow = hwnd;

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

    while(GetMessage(&Msg, NULL, 0, 0) > 0)
    {
        if (!TranslateMDISysAccel(g_hMDIClient, &Msg))
        {
            TranslateMessage(&Msg);
            DispatchMessage(&Msg);
        }
    }
    return Msg.wParam;
}