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CObList operator=

Posted on 1998-07-27
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Last Modified: 2013-11-20

Hi All,

I'm trying to create a link list using MFC CObList. The list is loaded
ok, but now I need to create another list (nested) inside that list.
After making the list I have to assign it to a member variable (of
type CObList) in the parent list.
How can I write the operator= for CObList?
or Is there a better way.
Here's a sample (this is just a pseudo code):

class CNestedData : public CObject {...} //the nested node
class CNestedList : public CObList  {
      CNestedList &operator=(const CNestedList & nlist);
}
class CData : CObject {
      //my other data of vary type (int, double, CString...)
      CNestedList *nestedList;
}

and create the list like this:
Nested List:
      CNestedData nestedData(...); //inserting data
      CObList nList;
      nList.AddHead(nestedData);
Parent List:
      //inserting data and copy the
      //nested list to nestedList
      CData thedata(..., nList);
      CObList thelist;
      thelist.AddHead(thedata);

How do I insert the nested list into the CData list
("..." means other data I have to insert to the list).
I tried to write the operator= like this:
(This function works but the nested lists are added up)
CNestedList& CNestedList::operator=(const CNestedList& nlist)
{
      CNestedData *theCopy;

      if(clist.GetCount()){
            POSITION pos = clist.GetHeadPosition();
            while(pos){
                  theCopy = (CCopy *)clist.GetAt(pos);
                  AddHead(theCopy);
                  clist.GetNext(pos);
            }
      }
    return *this;
}

I'm fairly new to MFC. Thanks for any help.

TT.
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Question by:trongtran
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2 Comments
 
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Accepted Solution

by:
trestan earned 300 total points
ID: 1319788
Try to use pointer or reference to pass the address of the object into the class using it. E.g.:
In your CData class, declare a constructor like this: CData(..., CNestedList * TempList){nestedList=TempList}; Create the instance like this: CData thedata(..., &nList); Pls try to see if it works. BTW, you derived CNestedList from CObList, but you still use CObList in your codes. Did you mean to use it or just derived to overload "="?  
0
 

Author Comment

by:trongtran
ID: 1319789
You're right, I'm sorry. I did used the derived CNestedList instead of CObList. I tried to pass argument by reference but I still need to write the operator=, don't I? (class CObList doesn't have one).
Anyway, I realized that I can use AddHead(CObList *) function instead. Still it isn't loading the list right.
Is there a better way to create the nested list?.
0

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