Re: serialize args
On May 18, 1:00 am, "RB" <NoMail@NoSpam> wrote:
I have been experimenting with writing a map object to file
and reading it back. I have gotten it to work, but the document
serialize is in my FormView class can only be called from the
FILE SAVE menu (through the framework code), which is fine
but I might have need to call serialize from another location in
code based on user input to data.
(Note: short partial Serialization tutorial compiled with head-
compiler and debugged with head-debugger follows).
If all you want is to serialize an object, this is the simplest you
can do:
CSomeObjectWithDECLARE_SERIAL* pObj;
Store:
CFile F(NAME_HERE, CFile::modeWrite|CFile::modeCreate|
CFile::shareDenyWrite);
CArchive ar(&F, CArchive::store);
ar << pObj;
Load:
CFile F(NAME_HERE, CFile::modeRead|CFile::shareDenyWrite);
CArchive ar(&F, CArchive::load);
ar >> pObj;
(make sure that you don't have something you need in pObj prior to
loading.)
The above stores/loads an object that is on heap, along with class/
version information given my DECLARE/IMPLEMENT_SERIAL. Obviously, you
need to override Serialize in your object.
Now, in your case, the object is some map. Here's an example with a
int-to-object map:
class CMyObject : public CObject
{
public:
int member1;
CString member2;
CMyObject() : member1(0) {}
DECLARE_SERIAL(CMyObject);
void Serialize(CArchive& ar)
{
if (ar.IsStoring()) ar << member1 << member2;
else ar >> member1 >> member2;
}
};
IMPLEMENT_SERIAL(CMyObject, CObject, VERSIONABLE_SCHEMA|1);
template<> void AFXAPI SerializeElements(CArchive& ar, CMyObject**
pElements, INT_PTR nCount)
{
if (ar.IsStoring())
{
while (nCount--)
ar << *(pElements++);
}
else
{
while (nCount--)
ar >> *(pElements++);
}
}
(I presume that map holds objects on heap).
Important: SerializeElements must be "visible" by the compiler when
compiling any MFC template container that contains pointers to such
objects.
class CMyMap : public CMap<int, int, CMyObject*, CMyObject*>
{
DECLARE_SERIAL(CMyMap);
};
IMPLEMENT_SERIAL(CMyMap, CObject, VERSIONABLE_SCHEMA|1)
(then load / store as above.)
But that's not what you seem either. You actually want to save a
document at a random place. For that:
class CMyDoc : ...
{...
CMyMap* m_pMap;
void Serialize(CArhcive& ar)
{
if (ar.IsStoring()) ar << m_pMap;
else ar >> m_pMap;
}
};
.... then use OnSaveDocument. Override ReportSaveLoadException to
report any errors that happen during saving. That's it. (There's more
explanation behind what I wrote here, but serialization is not a short
subject).
Goran.
P.S. Document is not saved through operator<<, and hence no class info
nor schema version is saved. Because of that, it's a good idea to put
SerializeClass(RUNTIME_CLASS(CMyDoc)) at the top of Serialize for the
document and so one can use GetObjectSchema in a "standard" manner,
for a document. Documentation for SerializeClass speaks only about
using it for "base" class serialization, but AFAIK, there's nothing
wrong in using it to store "current" class information. That comes in
handy in the document case, and also whenever you have a non-pointer
member in a serializable class.
Goran.