Is it not possible to add our own menu items on the CHtmlView context menu?

Question

So I keep coming back to this article on CodeProject:

https://www.codeproject.com/Articles/4758/How-to-customize-the-context-menus-of-a-WebBrowser

I then realise

Answer 1

I have got to the bottom of this. There were a few key things that I learned along the way.

Concept 1

I was not away of the CHtmlView::OnShowContextMenu function which I needed to implement:

HRESULT CChristianLifeMinistryHtmlView::OnShowContextMenu(DWORD dwID, LPPOINT ppt,
    LPUNKNOWN pcmdtReserved, LPDISPATCH pdispReserved)
{
    return CustomContextMenu(ppt, pcmdtReserved);
}

In my defence, the IDE in Visual Studio did not offer it in the list as a possibly override. But it existed non-the-less.

Concept 2

The menu IDs for all custom menu items fall between IDM_MENUEXT_FIRST__ and IDM_MENUEXT_LAST__ for a maximum of 33 custom commands. In my case I manually create some #define values in my resource.h file:

#define CUSTOM_MENU_PRINT_PREVIEW       3700
#define CUSTOM_MENU_EXPORT              3701

Note that I am not happy using literal values. I wish I could use IDM_MENU_EXT_FIRST + 1 etc. for my definitions but I do not know how to do that. Possible?

Concept 3

When you design your custom menu you can infill existing commands with the IDM_XXX values too:

IDR_MENU_HTML_POPUP MENU
BEGIN
    POPUP "CustomPopup"
    BEGIN
        MENUITEM "Select All",                  31
        MENUITEM SEPARATOR
        MENUITEM "Export",                      CUSTOM_MENU_EXPORT
        MENUITEM SEPARATOR
        MENUITEM "Page Setup",                  2004
        MENUITEM "Print Preview",               CUSTOM_MENU_PRINT_PREVIEW
        MENUITEM SEPARATOR
        MENUITEM "Refresh",                     2300
        MENUITEM SEPARATOR
        MENUITEM "View Source",                 2139
    END
END

The same note still applies though. I can't work out how to assign the IDM_* constants to my own #defines rather than using literal values.

Your custom menu items will be greyed out if you don't use the right ID values.

Concept 4

Then you have to create the context menu (see original question for that code).

Concept 5

This is closely related to item 4. TrackMenuPopup needed to be adjusted in my situation as follows:

// Show shortcut menu
iSelection = ::TrackPopupMenu(hPopupMenu,
    TPM_LEFTALIGN | TPM_RIGHTBUTTON | TPM_RETURNCMD,
    ppt->x,
    ppt->y,
    0,
    hwnd,
    (RECT*)NULL);

// Send selected shortcut menu item command to shell
if (iSelection != 0)
{
    if (iSelection == CUSTOM_MENU_PRINT_PREVIEW)
    {
        ::SendMessage(GetParent()->GetSafeHwnd(), WM_COMMAND, ID_FILE_PRINTPREVIEW, NULL);
    }
    else if (iSelection == CUSTOM_MENU_EXPORT)
    {
        ::SendMessage(GetParent()->GetSafeHwnd(), WM_COMMAND, ID_FILE_EXPORT, NULL);
    }
    else
    {
        (void) ::SendMessage(hwnd, WM_COMMAND, iSelection, NULL);
    }
}

The key was testing the return value of TrackMenuPopup and doing custom handling. In-fact, whilst writing this answer I now realise that my "Print Preview" menu item can be defined as the value of IDM_PRINTPREVIEW and I test again that, like this:

if (iSelection != 0)
{
    if (iSelection == IDM_PRINTPREVIEW)
    {
        ::SendMessage(GetParent()->GetSafeHwnd(), WM_COMMAND, ID_FILE_PRINTPREVIEW, NULL);
    }
    else if (iSelection == CUSTOM_MENU_EXPORT)
    {
        ::SendMessage(GetParent()->GetSafeHwnd(), WM_COMMAND, ID_FILE_EXPORT, NULL);
    }
    else
    {
        (void) ::SendMessage(hwnd, WM_COMMAND, iSelection, NULL);
    }
}

So my only gripe is that my own #define are values are using literal numbers and I would prefer them to be based on the IDM constants if possible. But either way, it all works fine!