Re: Fields not longer available when subclassing the _RecordsetPtr cla

From: Stephen Howe (stephenPOINThoweATtns-globalPOINTcom)
Date: 01/24/05 

Date: Mon, 24 Jan 2005 19:11:45 -0000

> I am using VC++ with ADO using the import pragma to access a local Access
> database with multiple tables. This access works correctly using
Fields->.
> I would like to subclass _RecordsetPtr to create different classes
specific
> to each table and to add functions to them (which are different for each
> table). In DAO every recordset class corresponds to a single table, and I
> would like something similar for ADO. After subclassing, the compiler no
> longer recognizes the Fields object. Classes are created with
> class TypeOneRecordSet :: public _RecordsetPtr {
> void DoSomethingTypeOne (void); }
> class TypeTwoRecordSet :: public _RecordsetPtr {
> void DoSomethingTypeTwo (void); }
> Error reports Fields not a member of a complicated COM object.

I don't think you want to do that.
I think you should be subclassing _Recordset (and it also will be a COM
object) and then do

_COM_SMARTPTR_TYPEDEF(TypeOneRecordSet, __uuidof(_TypeOneRecordSet));

It is _COM_SMARTPTR_TYPEDEF that adds "Ptr" to the end of each ADO Com type.
It creates smart pointers from ADO objects.
So you will get TypeOneRecordSetPtr

If you are using VC++ & ADO you probably have a #import statement.
This generates a file called msado15.tlh which is a header file.
Have a search in one of the Debug/Release directories for this file.
Have a look at this and notice the relationship between

Recordset15, Recordset20, Recordset21, _Recordset

_Recordset is a Recordset21
You want to do the same. That is the easiset way of getting what you want.

Stephen Howe

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