Using Tree Model to Store Data?

AlexanderAlexander

Currently:
I have created and populated a QTreeWidget with QTreeWidgetItems, and have set the text of the QTreeWidgetItems

Problem: I have no idea how to actually utilize the QTreeWidgetItems for data storage
Looking at: https://doc.qt.io/qt-5/qt.html#ItemDataRole-enum

void QTreeWidgetItem::setData(int column, int role, const QVariant &value)

I see that I can use a Qt::ItemDataRole to specify the type of data stored, but none of the options in the enumeration pertain to actually storing raw data, only Qt properties.

Questions:

How would I store actual data, such as doubles, within a WTreeWidgetItem?
If I am not supposed to actually store data within the tree items, do I need to use an auxilary structure and use model indexes with internal pointers to link the 2 together?

Info:

Qt5 (c++)
MSVC 2017 + Qt Designer[link text](link url)

Christian Ehrlicher

@AlexanderAlexander said in Using Tree Model to Store Data?:

How would I store actual data, such as doubles, within a WTreeWidgetItem?

You can store whatever you want in the QVariant.

VRonin

@AlexanderAlexander said in Using Tree Model to Store Data?:

I can use a Qt::ItemDataRole to specify the type of data stored

No. the Qt::ItemDataRole is just a "hint" about what you are storing. the type of data is completely determined by the variant. In all Qt native models Qt::DisplayRole and Qt::EditRole are exactly the same

I have no idea how to actually utilize the QTreeWidgetItems for data storage

Examples:

Set the text of the item in the first column: item->setData(0,Qt::DisplayRole,QStringLiteral("Hello"));
Set a numerical value as displayed in the first column: item->setData(0,Qt::DisplayRole,3.14);
Set the text colour for the the item in the first column: item->setData(0,Qt::ForegroundRole,QBrush(Qt::red));
Store a value that your program will use later: item->setData(0,Qt::UserRole,5);
Store another value that your program will use later: item->setData(0,Qt::UserRole+1,35);