🚀 go-pugleaf

"Nate Lockwood" <RNLockwoodREMOVE@attglobal.net> wrote in message
news:43ffba42$1@newsgroups.borland.com...

> I'd like to pass a StringList, too

You won't be able to do that.  Not directly, anyway.  You will have to make
a copy of the TStringList data and send it in full from one process to
another.  One way to do that is to use the WM_COPYDATA message.  You can use
the TStringList's Text property to get the data, ie:

    if( hWnd )
    {
        AnsiString sData = MyStringList->Text;
        COPYDATASTRUCT cds = {0};
        cds.dwData = WM_MYMSG;
        cds.cbData = s.Length();
        cds.lpData = sData.c_str();
        ::SendMessage(hWnd, WM_COPYDATA, 0, reinterpret_cast<LPARAM>(&cds));
    }

    //...

    __fastcall TFormMail::TFormMain(TComponent *Owner)
        : TForm(Owner)
    {
        Application->HookMainWindow(AppMessageHook);
    }

    __fastcall TFormMail::~TFormMain()
    {
        Application->UnhookMainWindow(AppMessageHook);
    }

    bool __fastcall TFormMain::AppMessageHook(TMessage &Message)
    {
        if( Message.Msg == WM_INITDIALOG )
            return true;

        if( Message.Msg == WM_COPYDATA )
        {
            LPCOPYDATASTRUCT lpcds =
reinterpret_cast<LPCOPYDATASTRUCT>(Message.LParam);
            if( (lpcds->dwData == WM_MYMSG) && (WM_MYMSG != 0) )
            {
                MyStringList->Text =
AnsiString(static_cast<char*>(lpcds->lpData), lpcds->cbData);
                return true;
            }
        }

        return false;
    }

> do I understand correctly that I can create a StringList
> in the heap, pass its address in one of the parameters?

No.  Different processes, even when launched from the same executable file,
have different address spaces from each other.  A memory address in one
process is not a valid address in another process.


Gambit