How to modify a CEdit context menu

Introduction

Have you ever wanted to modify the context menu of an edit control? You would start by overriding the OnInitMenuPopup() function only to find that the edit control does not post a WM_INITMENUPOPUP message, so your function is never called. Well, here is a simple CEdit derived class that you can use.

The CMenuEdit class

The CMenuEdit class does its job with just two functions, OnContextMenu() and OnCommand().

The OnContextMenu() function gets called when a user right-clicks on the edit control. In our override, we create a new popup menu that exactly duplicates the default context menu, and we call TrackPopupMenu() on that menu. By doing this, a WM_INITMENUPOPUP message is posted, which can then be handled in a class derived from CMenuEdit.

The OnCommand() function handles commands generated when a user selects an item from the menu. If the command is not generated by our menu, it is passed onto CEdit::OnCommand().

You can either derive your edit class from CMenuEdit or include these two functions in your class.

Updates

September 17, 2001 - Now handles read-only edit controls

The Source Files

The Header file

// MenuEdit.h : header file
// Written by PJ Arends
// pja@telus.net
// http://www3.telus.net/pja/

#if !defined(AFX_MENUEDIT_H__8EA53611_FD2B_11D4_B625_D04FA07D2222__INCLUDED_)
#define AFX_MENUEDIT_H__8EA53611_FD2B_11D4_B625_D04FA07D2222__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif 

class CMenuEdit : public CEdit
{
public:
    CMenuEdit() {};

protected:
    virtual BOOL OnCommand(WPARAM wParam, LPARAM lParam);
    afx_msg void OnContextMenu(CWnd* pWnd, CPoint point);

    DECLARE_MESSAGE_MAP()
};

#endif 

The Source file

// MenuEdit.cpp : implementation file
// Written by PJ Arends
// pja@telus.net
// http://www3.telus.net/pja/

#include "stdafx.h"
#include "MenuEdit.h"

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

#define MES_UNDO        _T("&Undo")
#define MES_CUT         _T("Cu&t")
#define MES_COPY        _T("&Copy")
#define MES_PASTE       _T("&Paste")
#define MES_DELETE      _T("&Delete")
#define MES_SELECTALL   _T("Select &All")
#define ME_SELECTALL    WM_USER + 0x7000

BEGIN_MESSAGE_MAP(CMenuEdit, CEdit)
    ON_WM_CONTEXTMENU()
END_MESSAGE_MAP()

void CMenuEdit::OnContextMenu(CWnd* pWnd, CPoint point)
{
    SetFocus();
    CMenu menu;
    menu.CreatePopupMenu();
    BOOL bReadOnly = GetStyle() & ES_READONLY;
    DWORD flags = CanUndo() && !bReadOnly ? 0 : MF_GRAYED;
    menu.InsertMenu(0, MF_BYPOSITION | flags, EM_UNDO,
        MES_UNDO);

    menu.InsertMenu(1, MF_BYPOSITION | MF_SEPARATOR);

    DWORD sel = GetSel();
    flags = LOWORD(sel) == HIWORD(sel) ? MF_GRAYED : 0;
    menu.InsertMenu(2, MF_BYPOSITION | flags, WM_COPY,
        MES_COPY);

    flags = (flags == MF_GRAYED || bReadOnly) ? MF_GRAYED : 0;
    menu.InsertMenu(2, MF_BYPOSITION | flags, WM_CUT,
        MES_CUT);
    menu.InsertMenu(4, MF_BYPOSITION | flags, WM_CLEAR,
        MES_DELETE);

    flags = IsClipboardFormatAvailable(CF_TEXT) &&
        !bReadOnly ? 0 : MF_GRAYED;
    menu.InsertMenu(4, MF_BYPOSITION | flags, WM_PASTE,
        MES_PASTE);

    menu.InsertMenu(6, MF_BYPOSITION | MF_SEPARATOR);

    int len = GetWindowTextLength();
    flags = (!len || (LOWORD(sel) == 0 && HIWORD(sel) ==
        len)) ? MF_GRAYED : 0;
    menu.InsertMenu(7, MF_BYPOSITION | flags, ME_SELECTALL,
        MES_SELECTALL);

    menu.TrackPopupMenu(TPM_LEFTALIGN | TPM_LEFTBUTTON |
        TPM_RIGHTBUTTON, point.x, point.y, this);
}

BOOL CMenuEdit::OnCommand(WPARAM wParam, LPARAM lParam)
{
    switch (LOWORD(wParam))
    {
    case EM_UNDO:
    case WM_CUT:
    case WM_COPY:
    case WM_CLEAR:
    case WM_PASTE:
        return SendMessage(LOWORD(wParam));
    case ME_SELECTALL:
        return SendMessage (EM_SETSEL, 0, -1);
    default:
        return CEdit::OnCommand(wParam, lParam);
    }
}