How to add an QObject to QListWidget

[steg90]

Hi,

Is it possible to add an object to a list widget item? In MFC I generally attach objects to items in a list, example ( this is from MFC ):

m_MessageList.SetItemDataPtr( nIndex, (void*)pMess );

m_MessageList.SetItemDataPtr( nIndex, (void*)pMess );

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Where pMess is of type CMessage ( own class ) and m_MessageList is of CListBox.

Best regards,
Steve

[jpn]

You can store anything a QVariant can hold as user data:

// QVariant data;
// QListWidgetItem* item;
item->setData(Qt::UserRole, data);

// QVariant data;
// QListWidgetItem* item;
item->setData(Qt::UserRole, data);

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See Q_DECLARE_METATYPE() in case built-in datatypes supported by QVariant are not enough.

[steg90]

Hi,

Thanks, that is exactly what I just did

Now, having trouble getting the item data back.

CDADcb::CMessage* pMess = ui.messageList->item(i)->data(Qt::UserRole);

CDADcb::CMessage* pMess = ui.messageList->item(i)->data(Qt::UserRole);

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Keeps saying cannot convert to CDADcb::CMessage from QVariant, I've tried casting this but to no avail.

Kind regards,
Steve

[jpn]

Try:

CDADcb::CMessage* pMess = ui.messageList->item(i)->data(Qt::UserRole).value<CDADcb::CMessage*>();

CDADcb::CMessage* pMess = ui.messageList->item(i)->data(Qt::UserRole).value<CDADcb::CMessage*>();

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[steg90]

Thanks JPN, you're a star

BTW, did have to do the following in the class header :

Q_DECLARE_METATYPE(CDADcb::CMessage*)

Q_DECLARE_METATYPE(CDADcb::CMessage*)

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[steg90]

Problem now is, pMess is always NULL?

This is how I set up the list box :

CDADcb::CMessage* pMess = (CDADcb::CMessage*)i.value();
if( pMess )
{
	QListWidgetItem *newItem = new QListWidgetItem;
	newItem->setFlags( newItem->flags() | Qt::ItemIsUserCheckable );
	newItem->setCheckState(Qt::Unchecked);
	newItem->setText( pMess->name );
	newItem->setData( Qt::UserRole, pMess );
                ui.messageList->insertItem( ui.messageList->count(), newItem);
}

CDADcb::CMessage* pMess = (CDADcb::CMessage*)i.value();
if( pMess )
{
	QListWidgetItem *newItem = new QListWidgetItem;
	newItem->setFlags( newItem->flags() | Qt::ItemIsUserCheckable );
	newItem->setCheckState(Qt::Unchecked);
	newItem->setText( pMess->name );
	newItem->setData( Qt::UserRole, pMess );
                ui.messageList->insertItem( ui.messageList->count(), newItem);
}

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Dunno what is wrong???

Regards,
Steve

[jpn]

newItem->setData( Qt::UserRole, QVariant::fromValue(pMess) );

newItem->setData( Qt::UserRole, QVariant::fromValue(pMess) );

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[steg90]

Once again, many thanks for all your great help, now works a treat

Kind regards,
Steve