VC++的菜單控制和自繪菜單。

菜單控制
爲什麼即使調用EnableMenuItem菜單項後，菜單項還處於禁止狀態  

需要將CFrameWnd:: m_bAutomenuEnable設置爲FALSE，如果該數據成員爲TRUE（缺省值），工作框將自動地禁止沒有ON_UPDATE_COMMAND_UI或者ON_COMMAND的菜單項。

//Disable MFC from automatically disabling menu items.

m_bAuoMenuEnable=FALSE;

//Now enable the menu item.

CMenu* pMenu=GetMenu ();

ASSERT_VALID (pMenu);

pMenu->EnableMenuItem (ID_MENU_ITEM,MF_BYCOMMAND | MF_ENABLED);



如何給系統菜單添加一個菜單項  

給系統菜單添加一個菜單項需要進行下述三個步驟：

首先，使用Resource Symbols對話（在View菜單中選擇Resource Symbols．．．

可以顯示該對話）定義菜單項ID，該ID應大於0x0F而小於0xF000；

其次，調用CWnd::GetSystemMenu獲取系統菜單的指針並調用CWnd:: Appendmenu將菜單項添加到菜單中。下例給系統菜單添加兩個新的菜單項：

int CMainFrame:: OnCreate (LPCREATESTRUCT lpCreateStruct)

{

…

//Make sure system menu item is in the right range.

ASSERT (IDM_MYSYSITEM &0xFFF0)==IDM_MYSYSITEM);

ASSERT (IDM-MYSYSITEM<0xF000);

//Get pointer to system menu.

CMenu* pSysmenu=GetSystemmenu (FALSE);

ASSERT_VALID (pSysMenu);

//Add a separator and our menu item to system menu.

CString StrMenuItem (_T ("New menu item"));

pSysMenu->Appendmenu (MF_SEPARATOR);

pSysMenu->AppendMenu (MF_STRING, IDM_MYSYSITEM, strMenuitem);

…

}

現在，選擇系統菜單項時用戶應進行檢測。使用ClassWizard處理

WM_SYSCOMMAND消息並檢測用戶菜單的nID參數：

void CMainFrame:: OnSysCommand (UINT nID,LPARAM lParam)

{

//Determine if our system menu item was selected.

if ( (nID & 0xFFF0)==IDM_MYSYSITEM)

{

//TODO-process system menu item

}

else

CMDIFrameWnd:: OnSysCommand (nID, lParam);

}

最後，一個設計良好的UI應用程序應當在系統菜單項加亮時在狀態條顯示一個幫助信息，這可以通過增加一個包含系統菜單基ID的串表的入口來實現。



如何確定頂層菜單所佔據的菜單行數  

這可以通過簡單的減法和除法來實現。首先，用戶需要計算主框窗口的高度和客戶區；其次，從主框窗口的高度中減去客戶區、框邊界以及標題的高度；最後，除以菜單欄的高度。下例成員函數是一個計算主框菜單所佔據的行數的代碼實現。

int CMainFrame:: GetMenuRows ()

{

CRect rcFrame,rcClient;

GetWindowRect (rcFrame);

GetClientRect (rcClient);

return (rcFrame.Height () -rcClient.Height ()-

:: GetSystemMetrics (SM_CYCAPTION) -

(:: getSystemMetrics (SM_CYFRAME) *2)) /

:: GetSystemMetrics (SM_CYMENU);

}




自繪菜單
聞怡洋譯

在這裏提供一個C++類(CCustomMenu)，該類是CMenu的子類，並且擁有自繪能力。它可以向你提供以下的功能：

設置字體顏色。
設置高亮度顏色。
設置高亮度時的風格。
設置選中時和在普通狀態下的菜單顯示的圖標。
設置顯示圖標大小。
在CCustomMenu中定義了結構MENUDATA，你必須根據你的需要填充該結構，並且在增加菜單時提供該結構的指針(調用AppendMenu,InsertMenu)。下面是一個例子：

1、定義CCustomMenu的實例，和MENUDATA結構變量。

    CCustomMenu m_cCustomMenu;
    MENUDATA menuData [8]; // as many menu items are present , You should be able to use
                //new and do the same
2、調用CreateMenu()設置有關參數。
    m_customMenu.CreateMenu ();
    m_customMenu.SetIconSize (25,25); //This is to set the size of the Icon.
                        // This should be used only once for any menu
    // in order to resize it, destroy and create the menu again with different size.
    m_customMenu.SetHighlightStyle (Normal); //Or TextOnly, if you want the
    // background color to remain the same
    // and the Text color to change to the Highlight color.
        // The following setXXXColor sets the menu colors. If you dont want to change any, Dont call these member functions.
     m_customMenu.SetTextColor (RGB (255,0,0));
     m_customMenu.SetBackColor (RGB (255,255,255));
     m_customMenu.SetHighlightColor (RGB (0,0,255));
3、設置MENUDATA變量，並增加菜單項。
     lstrcpy (menuData[0].menuText , "text1");
     menuData[0].menuIconNormal= IDI_ICON1;
     m_customMenu.AppendMenu (MF_OWNERDRAW,3,(LPCTSTR)menuData);

3、在你的窗口中重載OnMeasureItem(...)函數。
void CMyView::OnMeasureItem(int nIDCtl, LPMEASUREITEMSTRUCT lpMeasureItemStruct)
{
    if ( lpMeasureItemStruct->CtlType == ODT_MENU &&
            IsMenu((HMENU)lpMeasureItemStruct->itemID) &&
            (lpMeasureItemStruct->itemID == (UINT)m_hMenuSub) )
    {
        m_customMenu.MeasureItem (lpMeasureItemStruct);
    }
    else
        // let MFC's self-drawing handle it
        CView::OnMeasureItem(nIDCtl, lpMeasureItemStruct);
}

下面的函數將幫助你設置菜單屬性。

    void SetTextColor (COLORREF );
    void SetBackColor (COLORREF);
    void SetHighlightColor (COLORREF);
    void SetIconSize (int, int);
    void SetHighlightStyle (HIGHLIGHTSTYLE ); // HIGHLIGHTSTYLE : enum {Normal, TextOnly}
    void SetHighlightTextColor (COLORREF);



下面是文件代碼：
//*************************************************************************
// CustomMenu.h : header file
//

#if
!defined(AFX_CUSTOMMENU_H__FE5B01C3_1E02_11D1_B87A_0060979CDF6D__INCLUDED_)
#define AFX_CUSTOMMENU_H__FE5B01C3_1E02_11D1_B87A_0060979CDF6D__INCLUDED_

#if _MSC_VER >= 1000
#pragma once
#endif // _MSC_VER >= 1000
class MENUDATA
{
public:
    MENUDATA () { menuIconNormal = -1; menuIconSelected = -1;};
    char menuText[32];
    UINT menuIconNormal;
    UINT menuIconSelected;
};


typedef enum {Normal,TextOnly} HIGHLIGHTSTYLE;

////////////////////////////////////////////////
//
// CCustomMenu window

class CCustomMenu : public CMenu
{
// Construction
public:
    CCustomMenu();

// Attributes
public:

// Operations
public:

// Overrides
    // ClassWizard generated virtual function overrides
    //{{AFX_VIRTUAL(CCustomMenu)
    //}}AFX_VIRTUAL

// Implementation
public:
    virtual ~CCustomMenu();
    virtual void DrawItem( LPDRAWITEMSTRUCT);
    virtual void MeasureItem( LPMEASUREITEMSTRUCT );
    void SetTextColor (COLORREF );
    void SetBackColor (COLORREF);
    void SetHighlightColor (COLORREF);
    void SetIconSize (int, int);
    void SetHighlightStyle (HIGHLIGHTSTYLE );
    void SetHighlightTextColor (COLORREF);

    // Generated message map functions
protected:
    COLORREF m_crText;
    COLORREF m_clrBack;
    COLORREF m_clrText;
    COLORREF m_clrHilight;
    COLORREF m_clrHilightText;
    LOGFONT m_lf;
    CFont m_fontMenu;
    UINT m_iMenuHeight;
    BOOL m_bLBtnDown;
    CBrush m_brBackground,m_brSelect;
    CPen m_penBack;
    int m_iconX,m_iconY;
    HIGHLIGHTSTYLE m_hilightStyle;

    //{{AFX_MSG(CCustomMenu)
        // NOTE - the ClassWizard will add and remove member functions here.
    //}}AFX_MSG
};

///////////////////////////////////////
//

//{{AFX_INSERT_LOCATION}}
// Microsoft Developer Studio will insert additional declarations immediately before the previous line.

#endif //!defined(AFX_CUSTOMMENU_H__FE5B01C3_1E02_11D1_B87A_0060979CDF6D__INCLUDED_)

//*************************************************************************
// CustomMenu.cpp : implementation file
//

#include "stdafx.h"
#include "CustomMenu.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

////////////////////////////////////////////////
//
// CCustomMenu

CCustomMenu::CCustomMenu()
{
    m_clrText = GetSysColor (COLOR_MENUTEXT);
    m_clrBack = GetSysColor (COLOR_MENU);
    m_brBackground.CreateSolidBrush (m_clrBack);
    m_penBack.CreatePen (PS_SOLID,0,m_clrBack);
    m_crText = m_clrText;
    m_bLBtnDown = FALSE;
    m_iconX = GetSystemMetrics ( SM_CXMENUCHECK);
    m_iconY = GetSystemMetrics (SM_CYMENUCHECK );

    m_clrHilight = GetSysColor (COLOR_HIGHLIGHT);
    m_brSelect.CreateSolidBrush (m_clrHilight);
    m_clrHilightText = GetSysColor (COLOR_HIGHLIGHTTEXT);

    ZeroMemory ((PVOID) &m_lf,sizeof (LOGFONT));
    NONCLIENTMETRICS nm;
    nm.cbSize = sizeof (NONCLIENTMETRICS);

    //Get the system metrics for the Captionfromhere
    VERIFY (SystemParametersInfo (SPI_GETNONCLIENTMETRICS,0,&nm,0));

    m_lf = nm.lfMenuFont;
    m_iMenuHeight = nm.iMenuHeight;
    m_fontMenu.CreateFontIndirect (&m_lf);
}

CCustomMenu::~CCustomMenu()
{
    if ((HBRUSH) m_brBackground != NULL)
        m_brBackground.DeleteObject ();
    if ((HFONT)m_fontMenu !=NULL)
        m_fontMenu.DeleteObject ();
    if ((HBRUSH)m_brSelect != NULL)
         m_brSelect.DeleteObject ();
}



////////////////////////////////////////////////
//
// CCustomMenu message handlers


void CCustomMenu::DrawItem (LPDRAWITEMSTRUCT lpDIS)
{
    ASSERT(lpDIS != NULL);

    CDC* pDC = CDC::FromHandle(lpDIS->hDC);
    CRect rect;
    HICON hIcon;
    COLORREF crText = m_crText;
    // draw the colored rectangle portion
    rect.CopyRect(&lpDIS->rcItem);

    // draw the up/down/focused/disabled state

    UINT action = lpDIS->itemAction;
    UINT state = lpDIS->itemState;
    CString strText;
    LOGFONT lf;
    lf = m_lf;

    CFont dispFont;
    CFont *pFont;
    //GetWindowText(strText);
    if (lpDIS->itemData != NULL)
    {
        strText = (((MENUDATA*) (lpDIS->itemData))->menuText);
        if ((((MENUDATA *)(lpDIS->itemData))->menuIconNormal) == -1)
            hIcon = NULL;
        else if (state & ODS_SELECTED)
        {
            if ((((MENUDATA *)(lpDIS->itemData))->menuIconSelected) != -1)
                hIcon = AfxGetApp ()->LoadIcon (((MENUDATA *)(lpDIS->itemData))->menuIconSelected);
            else
                hIcon = AfxGetApp()->LoadIcon (((MENUDATA*)(lpDIS->itemData))->menuIconNormal);
        }
        else
            hIcon = AfxGetApp()->LoadIcon (((MENUDATA*)(lpDIS->itemData))->menuIconNormal);

        TRACE1 ("Draw for %s/n", strText);
    }
    else
    {
        strText.Empty();
        hIcon = NULL;
    }

    if ( (state & ODS_SELECTED) )
    {
        // draw the down edges

        CPen *pOldPen = pDC->SelectObject (&m_penBack);

        //You need only Text highlight and thats what you get
        if (m_hilightStyle != Normal)
        {
            pDC->FillRect (rect,&m_brBackground);
        }
        else
        {
            pDC->FillRect (rect,&m_brSelect);
        }

        pDC->SelectObject (pOldPen);
        pDC->Draw3dRect (rect,GetSysColor (COLOR_3DHILIGHT),GetSysColor(COLOR_3DSHADOW));
        lf.lfWeight = FW_BOLD;
        if ((HFONT)dispFont != NULL)
            dispFont.DeleteObject ();
        dispFont.CreateFontIndirect (&lf);
        crText = m_clrHilightText;

        //While selected move the text a bit
        TRACE0 ("SELECT,SELECTED/n");
    }
    else
    {
        CPen *pOldPen = pDC->SelectObject (&m_penBack);
        pDC->FillRect (rect,&m_brBackground);
        pDC->SelectObject (pOldPen);
        // draw the up edges
        pDC->Draw3dRect (rect,m_clrBack,m_clrBack);
        if ((HFONT)dispFont != NULL)
            dispFont.DeleteObject ();
        dispFont.CreateFontIndirect (&lf); //Normal

        TRACE0 ("SELECT, NORMAL/n");
    }

    // draw the text if there is any
    //We have to paint the text only if the image is nonexistant
    if (hIcon != NULL)
    {
        if(DrawIconEx (pDC->GetSafeHdc(),rect.left,rect.top,hIcon,
            (m_iconX)?m_iconX:32,(m_iconY)?m_iconY:32,0,NULL,DI_NORMAL))
            TRACE0("Wrote the icon successfully/n");
        else
            TRACE0 ("SORRY.NOGO/n");
    }
    //This is needed always so that we can have the space for check marks
    rect.left = rect.left +((m_iconX)?m_iconX:32);

    if ( !strText.IsEmpty())
    {
        // pFont->GetLogFont (&lf);

        int iOldMode = pDC->GetBkMode();

        pDC->SetBkMode( TRANSPARENT);

        pDC->SetTextColor( crText);

        pFont = pDC->SelectObject (&dispFont);
        TRACE1( "About To DrawText %s/n",strText);
        pDC->DrawText (strText,rect,DT_LEFT|DT_SINGLELINE|DT_VCENTER);
        TRACE0("Done/n");
        pDC->SetBkMode( iOldMode );
        pDC->SelectObject (pFont); //set it to the old font
    }
    dispFont.DeleteObject ();
}

void CCustomMenu::MeasureItem( LPMEASUREITEMSTRUCT lpMIS )
{
    CDC *pDC = AfxGetApp()->m_pMainWnd->GetDC();
    CFont* pFont = pDC->SelectObject (&m_fontMenu);
    int iconX = 0,iconY= 0;
    TEXTMETRIC tm;
    pDC->GetTextMetrics (&tm);
    pDC->SelectObject (pFont);
    AfxGetApp()->m_pMainWnd->ReleaseDC (pDC);

    if (m_iconX)
        iconX = m_iconX;
    if (m_iconY)
        iconY = m_iconY;

    lpMIS->itemWidth = iconX + tm.tmAveCharWidth * lstrlen(((MENUDATA*)(lpMIS->itemData))->menuText) +10;
    lpMIS->itemHeight = (iconY > (m_iMenuHeight+1))?iconY:m_iMenuHeight + 1;
}

void CCustomMenu::SetIconSize (int width, int height)
{
    m_iconX = width;
    m_iconY = height;
}

void CCustomMenu::SetTextColor (COLORREF clrText)
{
    m_crText = clrText;
}

void CCustomMenu::SetBackColor (COLORREF clrBack)
{
    m_clrBack = clrBack;
    if ((HBRUSH)m_brBackground != NULL)
        m_brBackground.DeleteObject ();
    m_brBackground.CreateSolidBrush (clrBack);
}

void CCustomMenu::SetHighlightColor (COLORREF clrHilight)
{
    m_clrHilight = clrHilight;
    if ((HBRUSH)m_brSelect != NULL)
            m_brSelect.DeleteObject ();
    m_brSelect.CreateSolidBrush (clrHilight);
}

void CCustomMenu::SetHighlightTextColor (COLORREF clrHilightText)
{
    m_clrHilightText = clrHilightText;
}


void CCustomMenu::SetHighlightStyle (HIGHLIGHTSTYLE hilightStyle)
{
    m_hilightStyle = hilightStyle;
}