Derive from the class CList in MFC

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Can we derive from the CList? If yes then how?
I tried following thing but I am getting the compile time error.

C++

class IIS_CList : public CList<cobject,>
{
...
}

I am not able to derive it from CList. How should we do it?

[Update]
thank you,

i followed what you said.

if i want to do this in generic way then what should we do for that?
means if i dont know whether the type is int, CString or may other
[/Update]

Posted 5-Sep-11 0:05am

sunnyram

Updated 5-Sep-11 0:43am

CPallini

v4

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CPallini · Accepted Answer · 2011-09-05T00:17:00

Solution 1

Yes, you may (of course) derive from CList, however the CList class as the following 'template signature' (see CList documentation[^]):

C++

template< class TYPE, class ARG_TYPE = const TYPE& > 
class CList : public CObject

Hence you should derive from accordingly, for instance

C++

class MyList : public CList <int, int >
{
  // ...
};

is allowed.

[Update]
If you want the same generality of the CList, in your class, then use:

C++

template  <class TYPE, class ARG_TYPE = const TYPE&> 
  class MyList : public CList < TYPE, ARG_TYPE  >
  {
    //..
  };

[/Update]

Posted 5-Sep-11 0:17am

CPallini

Updated 5-Sep-11 0:42am

v6

Comments

Eugen Podsypalnikov 5-Sep-11 6:34am

...it is also comfortable to use a type predefinition, for example :) :
typedef CList<int, int> CIntEntries;
class CMyRegs : private CIntEntries
{
..
void Reset() {
//.. some leaving actions
//..
CIntEntries::RemoveAll();
}
};

sunnyram 5-Sep-11 6:36am

thank you,

i followed what you said.

if i want to do this in generic way then what should we do for that?
means if i dont know whether the type is int, CString or may other

then what should we do for this
class MyList : public CList <cobject,cobject>
{
// ...
};
can we do like this?

i tried this i got the error like:
cannot access protected member declared in class 'CObject'

Eugen Podsypalnikov 5-Sep-11 6:41am

An int is not a CObject yet... :)
But you can control for example the VARIANTs in your list
or the pointers of CMyGenericValueBase. Then you could dirive some real values, for example CMyString : public CMyGenericValueBase and others... :)

sunnyram 5-Sep-11 6:48am

thank you