Question Regarding Automation

Hi,

I'm dealing with some automation for my code, and there is some syntax that is there that confuses me

I have code like this:

BEGIN_DISPATCH_MAP(MyDocument, CCmdTarget)
//{{AFX_DISPATCH_MAP(MyDocument)
DISP_FUNCTION(MyDocument, "SetVisible", SetVisible, VT_EMPTY, VTS_BOOL)
//}}AFX_DISPATCH_MAP
DISP_FUNCTION(MyDocument, "SetInvisible", SetInvisible, VT_EMPTY, VTS_BOOL)
END_DISPATCH_MAP()

The part i dont understand is why the AFX_DISPATH_MAP line is commented out And why all code between the AFX_DISPATH_MAP lines is a different colour (grayed out in VS2003). This functions must still work as they do in fact work, but what would the differrence be between the SetVisible and SetInvisible method calls. This style of commenting out the AFX_DISPATH_MAP lines is present in sample code at MSDN, but i cannot find an explanation for it In the example above, what in fact is the difference between the two differing lines referring to dispatch functions How do they behave differently, if at all, etc

Many thanks

Will

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Question Regarding Automation

uasking
Ok i have a fresh problem but with same thing, my code reads thus.

BEGIN_DISPATCH_MAP(MyDoc,COleServerDoc)

DISP_FUNCTION_ID(MyDoc, "GetScript", dispidGetScript, GetScript, VT_BSTR, VTS_NONE)
DISP_FUNCTION_ID(MyDoc, "SetPenColor", dispidSetPenColor, SetPenColor, VT_I4, VTS_I4)
DISP_FUNCTION(MyDoc, "GetBoxColor", GetBoxColor, VT_I4, VTS_NONE)

END_DISPATCH_MAP

that third line that refers to "GetBoxColor" is the one i am trying to add. It produces the following erros upon compiling

error C2146: syntax error: missing ';' before identifier 'TS_I4'
error C2146: syntax error: missing '}' before identifier 'TS_I4'
error C2146: syntax error: missing '}' before identifier 'TS_I4'
fatal error C1075: end of file found before the left brace '{' at 'myFileDoc.cpp(304)' was matched
line 304 refers to the line containing the DISP_FUNCTION_ID call to SetPenColor and is the line given for the other 3 problems as well.

I dont even have a clue here, any ideas

Will
German_Steffen
NO! Read part 2 again, don't get over start don't take the $400 :-)

If a function is called Save, there must be only 1 implementation there is NO overloading. This has nothing to do with C++ it is a OLE automation problem!
overseb
Ok thanks, will look into that idea, bit suprising that they wont allow the overloading though isnt it its a bit limiting

Will
Sing Hee
ok then, could i get away with this...

BEGIN_DISPATCH_MAP(STUFF, COleServer)
/*the change here is that the internal function used for saving is called save1*/
DISP_FUNCTION_ID(STUFF,"Save",dispidSave,Save1,VT_l4,VTS_NONE)
/*the internal function called here is just called save, which gets around the over-riding from the internal functions point of view, but the name still supplied in " " is the same*/
DISP_FUNCTION(STUFF,"Save",Save,VT_BOOL,VTS_BSTR)
END_DISPATCH_MAP

Would this work, sorry i know this one is a pain in the ***.

Will
Toranoshi22
Uhhh. This is complicated stuff.
1. About the dispatch ID
The macros DISP_FUNCTION/DISP_PARAMETER determines the Dispatch ID by position, so there is an internal counter. So rearranging the dispatch map usually causes a lot of clients to fail, if the just use the dispatch ID!
Read:
http://msdn.microsoft.com/library/default.asp url=/library/en-us/vclib/html/_mfcnotes_tn039.asp

DISP_FUNCTION_ID defines the specific dispatch ID.

2. COM/OLE does not support overloading.
A name and its parameters must be fixed. But! You can make all parameters VARIANT fields and support scode DISP_E_PARAMNOTFOUND! In the idl the parameters can be defined as optional.

HTH
irarabesc
So is there any difference between the two lines referring to DISP_FUNCTION

obviously the methods are different, but in the fundamental behavior is there any difference Also if this was just necessary for VC6, can i get rid of the commented lines in VS2003.
KLCurry
Ok, i see, so just so i understand this properly, this would work (although i cant see any point of it, just so i understand)

BEGIN_DISPATCH_MAP(STUFF, COleServer)
DISP_FUNCTION_ID(STUFF,"Save1",dispidSave,Save,VT_l4,VTS_NONE)
DISP_FUNCTION(STUFF,"Save",Save,VT_BOOL,VTS_BSTR)
END_DISPATCH_MAP

Different type of overloading, would it work

Thanks

Will
Marek Istvanek

No these lines are interpreted in the same way. You can remove the comments in VS.NET 200x!
Sampy
Yes! This will work. But the better implementation in my yes is the aproach I gave to you. Use VARIANTS for all arguments and allow them to be optional!
klingmeister
Hey,

thats great, one more question though, concerning overriding. I havent even checked if u can do this in c++ incidently (java guy originally).

Could i do this:

BEGIN_DISPATCH_MAP(STUFF,COleServerDoc)

/*this line should work*/
DISP_FUNCTION(STUFF,"Save",Save,VT_BOOL,VTS_BSTR)

/*will this work , in the sense that is is still a save message being called */
DISP_FUNCTION_ID(STUFF,"Save",dispidSave,Save,VT_l4,VTS_NONE)

/*will this realise that there are two different methods for save, each with different parameters, and call the correct one */
DISP_FUNCTION(STUFF,"Save",Save,VT_l4,VTS_NONE

END_DISPATCH_MAP()

Thanks

Will
ming_68
All //{{ comments are labels for the old VC6 source parser and class wizard. The old class wizard needed those remarks to change and insert those maps.
So in the old VC6 those parts should not be edited manually.
The new syntax parser still shows this colouring.
Daapower
Lol, sorry please ignore the last post, really daft mistake

sorry for wasting your time

will
zoe305
No its not! Remember that the OLE Automation interfaces are not designed to fit a OOP schema. IDispatch is an interface was speccifc rules. There is always a Name to Id relation.
jafar
ow ok, well thanks for your help

Will
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