【Windows编程】系列第十一篇：多文档界面框架

时间：2015-09-04 15:39:19 阅读：325 评论：0 收藏：0 [点我收藏+]

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前面我们所举的例子中都是单文档界面框架，也就是说这个窗口里面的客户区就是一个文档界面，可以编写程序在里面输入或者绘制文本和图形输出，但是不能有出现多个文档的情况。比如下面的UltraEdit就是一个典型的多文档界面，他可以同时编辑多个文档，每个文档还可以最大化，最小化等等，我们今天就来看看多文档的基本框架是怎么实现的。

技术分享

多文档界面的框架创建需要几下几步。

主框架窗口创建

主框架窗的创建跟普通的窗口没有什么区别，就是自己注册一个类并用该类创建一个重叠窗口，这个可以用CreateWindow/CreateWindowEx函数完成，主框架窗口可以用自己的菜单和状态栏。

客户区窗口创建

客户区创建的创建同样用你CreateWindow，但需要指定类为“MDICLIENT”，用这个类会创建多文档的客户区窗口。或者采用CreateWindowEx函数，指定扩展风格为WS_EX_MDICHILD。客户区不需要菜单和状态栏。

视图窗口创建

创建工作或者视图窗口作为实际文档窗口，这个也是需要自己注册类并创建自己需要的视图窗口。视图窗口可以有自己的菜单，一般不需要状态栏。当视图窗口激活时，主窗口的菜单需要替换成视图窗口的菜单，因为这个时候往往是对视图窗口进行操作，菜单替换也是理所当然的。菜单设置通过WM_MDISETMENU消息完成。该消息定义如下：

SendMessage(hWndControl, WM_MDISETMENU, wParam, lParam)
wParam表示新框架窗口菜单，
lParam表示要设置的菜单句柄

OK，基本的API就这些，下面我们直接上demo程序来演示，由于视图一般是一个多文档的实例，所以demo代码中用类来存储视图，每一个视图就是一个类的实例：

主文件，该文件包括主框架窗口、客户窗口已经视图窗口调用：

#include <windows.h>

#define CLIENT_WND_BGROUND

#define IDM_FIRSTCHILD 1001
#define IDM_FILE_NEW   1002

HINSTANCE g_hInst;
TCHAR     szMDIMainFrame[]= TEXT("MDI Main Frame");
TCHAR     gszAppName[]    = TEXT("MDI Demo");
HWND      ghWndMDIClient;
HWND      ghWndMainFrame;
HMENU     ghMainFrameMenu;

void CreateChildWndMenu(void);
HWND CreateDocView(HWND hParentWnd, HINSTANCE hInstance);
static LRESULT CALLBACK MainFrameProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

#ifdef CLIENT_WND_BGROUND
static WNDPROC pfOrigClientWndProc;
LRESULT CALLBACK ClientWndSubClassProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch(uMsg)
    {
    case WM_ERASEBKGND:
        {
            RECT rect;
            HDC hDC = (HDC)wParam;
            GetClientRect(hwnd, &rect);
            HBRUSH hbr = CreateSolidBrush(RGB(125, 150, 125));
            HBRUSH holdbr = (HBRUSH)SelectObject(hDC, hbr);
            FillRect(hDC, &rect, hbr);
            SelectObject(hDC, holdbr);
            DeleteObject(hbr);
        }
        return TRUE;
    default:
        break;
    }

    return CallWindowProc(pfOrigClientWndProc, hwnd, uMsg, wParam, lParam); 
}
#endif

HMENU CreateMainFrameMenu(void)
{
    //主框架菜单
    HMENU hMenu = CreateMenu();

    //文件菜单
    HMENU hFileMenu = CreateMenu();
    AppendMenu(hFileMenu, MF_STRING, IDM_FILE_NEW, TEXT("&New"));
    AppendMenu(hMenu, MF_POPUP, (UINT_PTR)hFileMenu, TEXT("&File"));

    return hMenu;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
    MSG msg;
    WNDCLASSEX wndclass = {0};

    wndclass.cbSize        = sizeof(WNDCLASSEX);
    wndclass.style        = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc    = MainFrameProc;
    wndclass.hInstance        = hInstance;
    wndclass.hIcon        = NULL;
    wndclass.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground    = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszClassName    = szMDIMainFrame;
    if(!RegisterClassEx(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"), gszAppName, MB_ICONERROR);
        return 0;
    }
    g_hInst = hInstance;

    ghMainFrameMenu = CreateMainFrameMenu();
    CreateChildWndMenu();

    //Create the main MDI frame window
    ghWndMainFrame = CreateWindow(szMDIMainFrame, 
                                gszAppName, 
                                WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN,
                                CW_USEDEFAULT,    // allows system choose an x position
                                CW_USEDEFAULT,    // allows system choose a y position
                                400,
                                300,
                                NULL,        // handle to parent window
                                ghMainFrameMenu,// handle to menu
                                hInstance,    // handle to the instance of module
                                NULL);        // Long pointer to a value to be passed to the window through the 
    ShowWindow(ghWndMainFrame,  SW_SHOW);
    UpdateWindow(ghWndMainFrame);

    while(GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg) ;
        DispatchMessage(&msg) ;
    }

    return msg.wParam ;
}

LRESULT CALLBACK MainFrameProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch(message)
    {
    case WM_CREATE:
        {
            CLIENTCREATESTRUCT ccs;
            ccs.hWindowMenu     = NULL;
            ccs.idFirstChild = IDM_FIRSTCHILD;
            ghWndMDIClient = CreateWindow(TEXT("MDICLIENT"), NULL,
                                        WS_CHILD | WS_CLIPCHILDREN | WS_VISIBLE,
                                        0, 0, 0, 0, hWnd, NULL,
                                        g_hInst, (void *)&ccs);
#ifdef CLIENT_WND_BGROUND
            pfOrigClientWndProc = (WNDPROC)SetWindowLong(ghWndMDIClient, GWL_WNDPROC, (LONG)ClientWndSubClassProc);
#endif
        }
        return 0;

    case WM_COMMAND:
        switch(LOWORD(wParam))
        {
        case IDM_FILE_NEW:
            CreateDocView(ghWndMDIClient, g_hInst);
            return 0;
        }
        break;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }

    return DefFrameProc(hWnd, ghWndMDIClient, message, wParam, lParam);
}

下面是视图窗口，每个视图窗口由一个类来描述，本文仅仅是一个demo，只有实例化一个视图窗口作为演示：

#include <windows.h>

#define IDM_EDIT_COPY 1003
#define IDM_EDIT_PASTE 1004

class CViewInfo
{
public:        
    CViewInfo(HINSTANCE hInst);
    ~CViewInfo();    
    HWND CreateViewWindow(HWND hParentWnd);
private:
    HINSTANCE m_hInst;
    HWND m_hWndView;
};

static TCHAR szViewWndName[] = TEXT("View Window");
static CViewInfo *g_pSystemInfo;
static HMENU      ghChildWndMenu;
extern HMENU      ghMainFrameMenu;

CViewInfo::CViewInfo(HINSTANCE hInst)
{
    m_hWndView = NULL;
    m_hInst = hInst;
}

CViewInfo::~CViewInfo()
{
    m_hWndView = NULL;
}

LRESULT CALLBACK ViewWindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch(message)
    {
    case WM_MDIACTIVATE:
        {
            HWND hWndClient = GetParent(hWnd);
            HWND hWndFrame  = GetParent(hWndClient);

            HMENU hMenu = GetSubMenu(ghChildWndMenu, 0);
            if (lParam == (LPARAM)hWnd)
            {
                SendMessage(hWndClient, WM_MDISETMENU, (WPARAM)ghChildWndMenu, (LPARAM)hMenu);
                EnableMenuItem(ghChildWndMenu, IDM_EDIT_COPY, MF_GRAYED);
            }

            // Set the framewindow menu if losing focus
            if (lParam != (LPARAM)hWnd)
            {
                SendMessage(hWndClient, WM_MDISETMENU, (WPARAM)ghMainFrameMenu, (LPARAM)NULL);
            }

            // call DrawMenuBar after the menu items are set
            DrawMenuBar(hWndFrame);

            return 0 ;
        }

    case WM_CLOSE:
        delete g_pSystemInfo;
        break;

    case WM_DESTROY:
        return 0;
    }

    return DefMDIChildProc(hWnd, message, wParam, lParam); //Frame window calls DefFrameProc rather than DefWindowProc
}


HWND CViewInfo::CreateViewWindow(HWND hParentWnd)
{
    WNDCLASSEX wcDoc;
    wcDoc.cbSize    = sizeof(WNDCLASSEX);
    wcDoc.style        = CS_HREDRAW | CS_VREDRAW;
    wcDoc.lpfnWndProc    = ViewWindowProc;
    wcDoc.cbClsExtra    = 0;
    wcDoc.cbWndExtra    = 0;
    wcDoc.hInstance    = m_hInst;
    wcDoc.hIcon        = NULL;
    wcDoc.hCursor    = LoadCursor(NULL, IDC_ARROW);
    wcDoc.hbrBackground    = (HBRUSH) GetStockObject(WHITE_BRUSH);
    wcDoc.lpszMenuName    = NULL;
    wcDoc.lpszClassName    = szViewWndName;
    wcDoc.hIconSm    = NULL;

    if(!RegisterClassEx(&wcDoc))
    {
        DWORD dw_LastError = GetLastError();
        if(ERROR_CLASS_ALREADY_EXISTS != dw_LastError)
        {
            return 0;
        }
    }

    m_hWndView = CreateWindowEx(WS_EX_MDICHILD, szViewWndName, 
                                TEXT("New view"), 0, CW_USEDEFAULT,
                                CW_USEDEFAULT, 300, 200,
                                hParentWnd, NULL, m_hInst, NULL);

    return m_hWndView;
}

HWND CreateDocView(HWND hParentWnd, HINSTANCE hInstance)
{
    HWND hView;

    g_pSystemInfo = new CViewInfo(hInstance);
    hView = g_pSystemInfo->CreateViewWindow(hParentWnd);
    if (hView == NULL)
    {
        delete g_pSystemInfo;
        g_pSystemInfo = NULL;
    }

    return hView;
}

void CreateChildWndMenu(void)
{
    //View菜单
    ghChildWndMenu = CreateMenu();

    //编辑菜单
    HMENU hEditMenu = CreateMenu();
    AppendMenu(hEditMenu, MF_STRING, IDM_EDIT_COPY, TEXT("&Copy"));
    AppendMenu(hEditMenu, MF_STRING, IDM_EDIT_PASTE, TEXT("&Paste"));
    AppendMenu(ghChildWndMenu, MF_POPUP, (UINT_PTR)hEditMenu, TEXT("&Edit"));
}