Two QStandardItem objects handling different attributes of same object

[jmborr]

I'm a newbie with the Model/View programming of Qt and have read the Editable Tree Model Example in the Qt documentation. In this example a single object (TreeItem) encapsulates two pieces of information that later are displayed in a single row containing two columns (name and description) thanks to overriding of QModelIndex QAbstractItemModel::index() and QVariant QAbstractItemModel::data().

I have a custom class (e.g. Foo) containing two pieces of information (Foo::m_name and Foo::m_description) that I want to display in a single row containing two columns, but instead of subclassing QAbstractItemModel I want to subclass QStandardItemModel because it has some much functionality. However, it seems I must create two QStandardItem objects, one to edit/display m_name and another to edit/display m_description. Is there some standard design scheme to manage a single Foo object in memory while having more than one QStandardItem object to handle different attributes of Foo?

[ChrisW67]

No, but you can subclass QAbstractTableModel to get much of the table handling logic for free and still have your own internal data structure.

[jmborr]

I just found a post in qtcentre suggested Chapter 4 of Advanced Qt Programming and lo and behold, there's a discussion of a tree subsclassing QstandardItemModel and QStandardItem where each row of the tree is made up of three QstandardItem objects handling different properties of a single object.
The implementation source code is freely available

Basically, one has:

class myItem : public QStandardItem {
    public:
      myItem(Foo &afoo) : QStandardItem(afoo.getName()), m_foo(afoo) {
        m_description = new QStandardItem(afoo.getDescription());
        }
      QstandardItem *m_description; // display m_description
    private:
      Foo &m_foo;    
    };

class myItem : public QStandardItem {
    public:
      myItem(Foo &afoo) : QStandardItem(afoo.getName()), m_foo(afoo) {
        m_description = new QStandardItem(afoo.getDescription());
        }
      QstandardItem *m_description; // display m_description
    private:
      Foo &m_foo;    
    };

To copy to clipboard, switch view to plain text mode 

and then we insert a row of two QstandardItem in our model tree

class myModel: public QStandardItemModel {
 
      StandardItem *myModel::appendRow(QStandardItem *parent, Foo &afoo)
      {
          auto *doublet = new myItem(afoo);
          parent->appendRow(QList<QStandardItem*>() << doublet
                  << double->m_description);
          return nameItem;  
      }
    }

class myModel: public QStandardItemModel {
      
      StandardItem *myModel::appendRow(QStandardItem *parent, Foo &afoo)
      {
          auto *doublet = new myItem(afoo);
          parent->appendRow(QList<QStandardItem*>() << doublet
                  << double->m_description);
          return nameItem;  
      }
    }

To copy to clipboard, switch view to plain text mode 

[anda_skoa]

Sounds like you would rather want a custom model that operates on your Foo objects.

Cheers,
_