[Qt-interest] Qt MVC Questions

[Sean Harmer]

On Sunday 20 Sep 2009 23:59:20 Willy P wrote:
> Sean,
> Thanks for writing back.  Late last night I came across the ProxyModel
> classes.  I inherited from QSortFilterProxyModel and am attempting to
> create mapTo / mapFrom source functions that, for starters, simply
> pass the the values back and forth with no modification.  It is not
> working at all:
>
>
> 	QModelIndex ReducedTreeModel::mapFromSource( const QModelIndex & source )
> const {
> 		qDebug() << "from Source" << source.row() << source.column() <<
> source.internalId();
> 		return createIndex( source.row(), source.column(), ( quint32
> )source.internalId() );
> 	}
>
>
>
> 	QModelIndex ReducedTreeModel::mapToSource( const QModelIndex& proxy )
> const {
> 		qDebug() << "to Source" << proxy.row() << proxy.column() <<
> proxy.internalId();
> 		return (sourceModel()&&proxy.isValid())
> 				? sourceModel()->index(proxy.row(), proxy.column(), proxy.parent())
>
> 				: QModelIndex();
>
> 	}
>
>
> Can you tell me what I'm doing wrong here?  It's crashing when an
> absolutely junk value comes into mapToSource for proxy.internalId().
>
> Thanks again...

I am guessing that it is crashing in the index() function of your source 
model. You need to ensure that the parent index is valid in your index 
function.

HTH,

Sean