Re: Request final critique
Goran wrote:
Yes, there was the message, but MFC continues with loading
(it does not know anything about your mesage box), which in the
end means that you seemingly start the app with document
C:\does\not\matter.yourfiletype open. But doc is actually empty,
because you didn't really load it. Now imagine that your user forgets
the message and saves what he has (an empty doc). Whoops!
OHhhhhh! I can now see what you are talking about. He would
have overwritten what "used to be" the file persistance of the doc.
What a shallow oversight on my part. You saved me on this.
Goran wrote:
Minor point: you should not be using string (text) information for
version. You have numbers anyhow, use them.
RB wrote:
If you would be so kind, please elaborate as to why a number would
be better than a string for this.
Goran wrote:
Look at the changes to your code to identify versions. You already
have text.Right(7) that won't work as soon as your version becomes
n.n.n.nn. Do you want to think about that (all the time, really)?
Integral number, OTOH, is an integral. x == y, that's it.
Ah yes, I can see your point now, before in my limited foresight I
never envisioned a build number going beyond 1 displacement.
In other words I thought if I reached build number 9, I would change
the version to 2. But I can see the fallacy in that now. I really have
never gotten that far along with anything I write.
Goran wrote:
number). Each time we change the schema, we bump that number,
(as well the schema number in the appropriate class).
Goran Wrote:
Additional comment here: what we do is OK, but the "more" MFC
way is to version-enable your document class and use SerializeClass,
e.g.
#define GENERAL_DOC_VERSION X
IMPLEMENT_SERIAL(
CYourDoc,
CYourDocBaseProbablyCDocument,
VERSIONABLE_SCHEMA|GENERAL_DOC_VERSION)
void CYourDoc::Serialize(...)
{
SerializeClass(GetRuntimeClass( ));
loading:
UINT nSchema Schema = GetObjectSchema( );
if (Schema > GENERAL_DOC_VERSION)
ExceptionTooNew( );
...
storing:
...
}
Notes:
* this ties serialization with your document class name, so you will
have trouble changing it
* any use of serializeClass or operator<</>> tie serialization with
your class name.
(That might be a problem when/if a major overhaul of serialization
occurs).
Albeit I do understand what you are saying about tieing to the
serialization, this brings to bear a whole cloud that I have been confused
on (but aware of ) for some time, and I know you explained this to me
before. But I have not completely parameritized all of the logistical
operations in the macros when I would expand them. Please see
below. My input and/or questions are in the // comments
/////////////////////////////////////////////////////
// CFileHandlingDoc
IMPLEMENT_DYNCREATE(CFileHandlingDoc, CDocument)
// Results in below macro, which appears to me to create the
// MyDocDerivative object passing FFFF as the schema (which is not
// a valid schema value but the default of -1 )
#define IMPLEMENT_DYNCREATE(class_name, base_class_name) \
CObject* PASCAL class_name::CreateObject( ) \
{ return new class_name; } \
IMPLEMENT_RUNTIMECLASS(class_name, base_class_name, 0xFFFF, \
class_name::CreateObject)
//---------------------------------------------------------------
// So I though all I had to do was set the schema from inside my doc
// as in:
CRuntimeClass* pMyDocRT = GetRuntimeClass( );
pMyDocRT->m_wSchema = 1; // set my schema
//---------------------------------------------------------------
// But if I run the IMPLEMENT_SERIAL macro on on MyDocDerivative
// after it is already in existence, isn't this going to create another occurance
// of it's CRuntimeClass ?
// I feel that I am still missing something in the structure here.
#define IMPLEMENT_SERIAL(class_name, base_class_name, wSchema) \
CObject* PASCAL class_name::CreateObject() \
{ return new class_name; } \
_IMPLEMENT_RUNTIMECLASS(class_name, base_class_name, wSchema, \
class_name::CreateObject) \
AFX_CLASSINIT _init_##class_name(RUNTIME_CLASS(class_name)); \
CArchive& AFXAPI operator>>(CArchive& ar, class_name* &pOb) \
{pOb = (class_name*) ar.ReadObject(RUNTIME_CLASS(class_name)); \
return ar; } \
Again thanks for speeding me along over mistakes I would have had
to learn the hard way. Greatly appreciated. If you lived near I would
buy you a round of beer (unless you are like Joe and don't drink).
;-) Beware, I live in Belgium now, so I am picky about beer ;-)
Goran.
Well if it is terribly expensive, how about a shot of Tequila with lime.
On second thought I owe you what ever beer you ask for.
Hopefully you will have the time and patience to respond to my
confusion above on the CRuntime ramifications..........RB