采用ATL实现无模板对话框的显示

在采用ATL、WTL的开发对话框程序的标准方法是从CDialogImpl上继承，然后在类中定义一个IDD，把这个窗口与资源关联起来。如果不定这个IDD是编译不通过的，代码如下：

class CAboutDlg : public CDialogImpl<CAboutDlg>
{
public:
    enum { IDD = IDD_ABOUTBOX };

    BEGIN_MSG_MAP(CAboutDlg)
        MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
        COMMAND_ID_HANDLER(IDOK, OnCloseCmd)
        COMMAND_ID_HANDLER(IDCANCEL, OnCloseCmd)
    END_MSG_MAP()

// Handler prototypes (uncomment arguments if needed):
//    LRESULT MessageHandler(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)
//    LRESULT CommandHandler(WORD /*wNotifyCode*/, WORD /*wID*/, HWND /*hWndCtl*/, BOOL& /*bHandled*/)
//    LRESULT NotifyHandler(int /*idCtrl*/, LPNMHDR /*pnmh*/, BOOL& /*bHandled*/)

    LRESULT OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/);
    LRESULT OnCloseCmd(WORD /*wNotifyCode*/, WORD wID, HWND /*hWndCtl*/, BOOL& /*bHandled*/);
};

在有些情况下，我们并不会采用窗口模板来创建窗口，而是对话框及所有的控件都采用自定义的方式来实现，比我们通过根据配置文件来生成控件列表。为了实现这个需求我开发一个无模板对话框类，代码如下：

typedef CWinTraits<WS_POPUP|WS_BORDER|WS_SYSMENU|DS_MODALFRAME|WS_CAPTION,
                            WS_EX_DLGMODALFRAME | WS_EX_CONTROLPARENT> CDialogWinTraits;


template <class T, class TWinTraits = CDialogWinTraits, class TBase = CWindow>
class ATL_NO_VTABLE CNTDialogImpl : public CDialogImplBaseT< TBase >
{
public:
#ifdef _DEBUG
    bool m_bModal;
    CNTDialogImpl() : m_bModal(false) { }
#endif //_DEBUG
    // modal dialogs
    virtual INT_PTR DoModal(HWND hWndParent = ::GetActiveWindow(), _U_RECT rect = NULL,
        LPCTSTR szWindowName = NULL, DWORD dwStyle = 0, DWORD dwExStyle = 0)
    {
        // 创建模板
        LPDLGTEMPLATE pTemplate = CreateDlgTemplate (dwStyle, dwExStyle, szWindowName);
        if (pTemplate == NULL) return -1;

        // 更新位置
        if (rect.m_lpRect)
        {
            pTemplate->x = (short)rect.m_lpRect->left;
            pTemplate->y = (short)rect.m_lpRect->right;
            pTemplate->cx = (short)(rect.m_lpRect->right - rect.m_lpRect->left);
            pTemplate->cy = (short)(rect.m_lpRect->bottom - rect.m_lpRect->top);
        }

        // 开始显示窗口
        ATLASSUME(m_hWnd == NULL);
        if (m_thunk.Init(NULL,NULL) == FALSE) 
        {
            SetLastError(ERROR_OUTOFMEMORY);
            return -1;
        }

        _AtlWinModule.AddCreateWndData(&m_thunk.cd, this);
    #ifdef _DEBUG
        m_bModal = true;
    #endif //_DEBUG

        LRESULT ret = DialogBoxIndirect(_AtlBaseModule.GetResourceInstance(),
                                pTemplate, hWndParent, T::StartDialogProc);

        GlobalFree(pTemplate);
        return ret;
    }
    BOOL EndDialog(int nRetCode)
    {
        ATLASSERT(::IsWindow(m_hWnd));
#ifdef _DEBUG
        ATLASSUME(m_bModal);    // must be a modal dialog
#endif //_DEBUG
        return ::EndDialog(m_hWnd, nRetCode);
    }

protected:
    LPWORD lpwAlign ( LPWORD lpIn)
    {
        ULONG ul = (ULONG) lpIn;
        ul +=3; ul >>= 2; ul <<= 2;
        return (LPWORD) ul;
    }

    // 创建对话框模板
    LPDLGTEMPLATE CreateDlgTemplate (DWORD dwStyle, DWORD dwExStyle, LPCTSTR szWindowName)
    {
        HGLOBAL hgbl = NULL;
        LPDLGTEMPLATE lpdt = NULL;
        LPWORD lpw = NULL;
        LPWSTR lpwsz = NULL;

        hgbl = GlobalAlloc(GMEM_ZEROINIT, 1024);
        if (!hgbl) return NULL;

        lpdt = (LPDLGTEMPLATE)GlobalLock(hgbl);

        // 定义窗口样式
        lpdt->style = TWinTraits::GetWndStyle (dwStyle);
        lpdt->dwExtendedStyle = TWinTraits::GetWndExStyle (dwExStyle);
        lpdt->cdit = 0;  // 窗口中的控件数量
        lpdt->x  = 0;
        lpdt->y  = 0;
        lpdt->cx = 100;    // 默认宽度
        lpdt->cy = 50;    // 默认高度

        lpw = (LPWORD) (lpdt + 1);
        *lpw++ = 0x0000;   // 没有菜单
        *lpw++ = 0x0000;   // 采用默认类

        lpwsz = (LPWSTR) lpw;
        int nchar = 0;
        if (szWindowName)
        {
            int slen = _tcslen(szWindowName) + 1;
            _tcsncpy_s (lpwsz, slen, szWindowName, slen);
            nchar = slen;
        }
        lpw   += nchar;

        GlobalUnlock(hgbl);
        return (LPDLGTEMPLATE) hgbl;
    }
};

使用方法为把从CDialogImpl上继承改为从CNTDialogImpl中继承就可以，而且不用再定义IDD：

class CAboutDlg : public CNTDialogImpl<CAboutDlg>
{
public:
    BEGIN_MSG_MAP(CAboutDlg)
        MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
        COMMAND_ID_HANDLER(IDCANCEL, OnCloseCmd)
    END_MSG_MAP()

    LRESULT OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/);
    LRESULT OnCloseCmd(WORD /*wNotifyCode*/, WORD wID, HWND /*hWndCtl*/, BOOL& /*bHandled*/);

};

在OnInitDialog中你可以创建你想到的控件，同时最好加上窗口居中的代码，否则窗口会显示在主窗口的左则，不太好看。代码如下：

LRESULT CAboutDlg::OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)
{
    CenterWindow(GetParent());  // 窗口居中
    ResizeClient (300, 200);    // 调整窗口大小
    //在以下窗口控件
    //.......

    return TRUE;
}