Re: Sendmessage: from one thread to mainthread (CFormView)

From:
Mikel Luri <mikel.luri+NOSPAM@gmail.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Wed, 08 Sep 2010 15:35:17 +0200
Message-ID:
<i683ej$5mr$1@speranza.aioe.org>
El 08/09/2010 15:13, mfc escribi?:

On 5 Sep., 23:09, Joseph M. Newcomer<newco...@flounder.com> wrote:

See below...

On Sun, 5 Sep 2010 11:01:36 -0700 (PDT), mfc<mfcp...@googlemail.com> wrote:

Hi,

I`m new to MFC; therefore I want to know if I do the right thing on
the right place :-). My mfc project is a unicode sdi application.

In my cdoc OnNewDocument class I load a xml file including all the
user-specific data. I hope this would be the right place to do that.
All xml nodes are stored in a cstringlist in the cdoc class.

BOOL CMIAppDoc::OnNewDocument()
{
if (!CDocument::OnNewDocument())
     return FALSE;

// Initialize COM
::CoInitialize(NULL);

//CStringList *m_XmlList; declaration in the cdoc header file
m_XmlList = XmlFile.LoadUserXml();

return TRUE;
}

To get this CStringList for each view - simple call
OnUpdateAllViews().

But which would be a suitable / recommend way to get the CStringList
m_XmlList to a non-mfc class?


****
Pretty much as you have already done. There's nothing there that is unique to the
CDocument-derived class.
****

For example, I`ve installed a webserver
with a class HttpServer, which loads the specific html resource and
adds these information (inlcuded in m_XmlList) to the webpage.

class HttpServer
{
public:
    HttpServer(void);
    ~HttpServer(void);
//and so on
}

BOOL HttpServer::GetFileRequest()
{
CString protoHTML("");
CString userHTML("");

//load html resource
if (GetHTML(id , protoHTML) == true)


****
Comparing this to 'true' is both dangerous and unnecessary. Get rid of the == true in the
above line!
****


Could you tell me why this line is dangerous? GetHTML is a function
which loads the html resource to protoHTML. If anything goes wrong
within this function -> FALSE will be returned instead of TRUE.


Hi, I guess Joe will tell you better, but it is:

- Unnecessary, because, if GetHTML already returns a boolean value, you
don't need to compare that boolean value with true or false again.

- Dangerous, because, among other things, there are functions whose
documentation says return TRUE or FALSE, but they don't. They return
FALSE and one or several non-0 values with different meanings.

TRUE is defined as 1, and FALSE as 0 (not to confuse with lowercase true
and false). And anything non-0 behaves like true, but it is not equal to
TRUE, so you could have trouble.

I once did something like:

CPath myPath;
// Get Path here

if (myPath.IsDirectory() == TRUE)
{
     // Do stuff
}

And it didn't get into the if block, because IsDirectory returns 16 when
the path is a directory (the docs say it returns TRUE), which evaluates
as non-false, but does not equal TRUE (1).

To avoid that problem, you could do
if(whatever != false)
{
}

but it is still unnecessary and error prone.

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