Qt 4.0: QItemSelectionModel Class Reference

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# QItemSelectionModel Class Reference
[QtGui module]

The QItemSelectionModel class keeps track of a view's selected items. More...

    #include <QItemSelectionModel>

Inherits QObject.

- List of all members, including inherited members

### Public Types

- enum SelectionFlag { NoUpdate, Clear, Select, Deselect, ..., ClearAndSelect }
- flags SelectionFlags

### Public Functions

- QItemSelectionModel ( QAbstractItemModel * model )
- virtual ~QItemSelectionModel ()
- bool columnIntersectsSelection ( int column, const QModelIndex & parent ) const
- QModelIndex currentIndex () const
- bool isColumnSelected ( int column, const QModelIndex & parent ) const
- bool isRowSelected ( int row, const QModelIndex & parent ) const
- bool isSelected ( const QModelIndex & index ) const
- const QAbstractItemModel * model () const
- bool rowIntersectsSelection ( int row, const QModelIndex & parent ) const
- QModelIndexList selectedIndexes () const
- const QItemSelection selection () const

- 28 public functions inherited from QObject

### Public Slots

- virtual void clear ()
- virtual void reset ()
- virtual void select ( const QModelIndex & index, QItemSelectionModel::SelectionFlags command )
- virtual void select ( const QItemSelection & selection, QItemSelectionModel::SelectionFlags command )
- void setCurrentIndex ( const QModelIndex & index, QItemSelectionModel::SelectionFlags command )

- 1 public slot inherited from QObject

### Signals

- void currentChanged ( const QModelIndex & current, const QModelIndex & previous )
- void currentColumnChanged ( const QModelIndex & current, const QModelIndex & previous )
- void currentRowChanged ( const QModelIndex & current, const QModelIndex & previous )
- void selectionChanged ( const QItemSelection & selected, const QItemSelection & deselected )

- 1 signal inherited from QObject

### Protected Functions

- void emitSelectionChanged ( const QItemSelection & newSelection, const QItemSelection & oldSelection )

- 7 protected functions inherited from QObject

### Additional Inherited Members

- 1 property inherited from QObject
- 4 static public members inherited from QObject

## Detailed Description

The QItemSelectionModel class keeps track of a view's selected items.

A QItemSelectionModel keeps track of the selected items in a view, or in several views onto the same model. It also keeps track of the currently selected item in a view.

The QItemSelectionModel class is one of the Model/View Classes and is part of Qt's model/view framework.

The selected items are stored using ranges. Whenever you want to modify the selected items use select() and provide either a QItemSelection, or a QModelIndex and a QItemSelectionModel::SelectionFlag.

The QItemSelectionModel takes a two layer approach to selection management, dealing with both selected items that have been committed and items that are part of the current selection. The current selected items are part of the current interactive selection (for example with rubber-band selection or keyboard-shift selections).

To update the currently selected items, use the bitwise OR of QItemSelectionModel::Current and any of the other SelectionFlags. If you omit the QItemSelectionModel::Current command, a new current selection will be created, and the previous one added to the committed selection. All functions operate on both layers; for example, selectedItems() will return items from both layers.

See also Model/View Programming and QAbstractItemModel.

## Member Type Documentation

### enum QItemSelectionModel::SelectionFlag
flags QItemSelectionModel::SelectionFlags

This enum describes the way the selection model will be updated.

Constant | Value | Description
--- | --- | ---
`QItemSelectionModel::NoUpdate` | `0x0000` | No selection will be made.
`QItemSelectionModel::Clear` | `0x0001` | The complete selection will be cleared.
`QItemSelectionModel::Select` | `0x0002` | All specified indexes will be selected.
`QItemSelectionModel::Deselect` | `0x0004` | All specified indexes will be deselected.
`QItemSelectionModel::Toggle` | `0x0008` | All specified indexes will be selected or deselected depending on their current state.
`QItemSelectionModel::Current` | `0x0010` | The current selection will be updated.
`QItemSelectionModel::Rows` | `0x0020` | All indexes will be expanded to span rows.
`QItemSelectionModel::Columns` | `0x0040` | All indexes will be expanded to span columns.
`QItemSelectionModel::SelectCurrent` | `Select | Current` | A combination of Select and Current, provided for convenience.
`QItemSelectionModel::ToggleCurrent` | `Toggle | Current` | A combination of Toggle and Current, provided for convenience.
`QItemSelectionModel::ClearAndSelect` | `Clear | Select` | A combination of Clear and Select, provided for convenience.

The SelectionFlags type is a typedef for QFlags<SelectionFlag>. It stores an OR combination of SelectionFlag values.

## Member Function Documentation

### QItemSelectionModel::QItemSelectionModel ( QAbstractItemModel * model )

Constructs a selection model that operates on the specified item model.

### QItemSelectionModel::~QItemSelectionModel () `[virtual]`

Destroys the selection model.

### void QItemSelectionModel::clear () `[virtual slot]`

Clears the selection model. Emits selectionChanged() and currentChanged().

### bool QItemSelectionModel::columnIntersectsSelection ( int column, const QModelIndex & parent ) const

Returns true if there are any items selected in the column with the given parent.

### void QItemSelectionModel::currentChanged ( const QModelIndex & current, const QModelIndex & previous ) `[signal]`

This signal is emitted whenever the current item changes. The previous model item index is replaced by the current index as the selection's current item.

See also currentIndex() and setCurrentIndex().

### void QItemSelectionModel::currentColumnChanged ( const QModelIndex & current, const QModelIndex & previous ) `[signal]`

This signal is emitted if the current item changes and its column is different to the column of the previous current item.

See also currentChanged(), currentRowChanged(), currentIndex(), and setCurrentIndex().

### QModelIndex QItemSelectionModel::currentIndex () const

Returns the model item index for the current item, or an invalid index if there is no current item.

See also setCurrentIndex().

### void QItemSelectionModel::currentRowChanged ( const QModelIndex & current, const QModelIndex & previous ) `[signal]`

This signal is emitted if the current item changes and its row is different to the row of the previous current item.

See also currentChanged(), currentColumnChanged(), currentIndex(), and setCurrentIndex().

### void QItemSelectionModel::emitSelectionChanged ( const QItemSelection & newSelection, const QItemSelection & oldSelection ) `[protected]`

Compares the two selections newSelection and oldSelection and emits selectionChanged() with the deselected and selected items.

### bool QItemSelectionModel::isColumnSelected ( int column, const QModelIndex & parent ) const

Returns true if all items are selected in the column with the given parent.

Note that this function is usually faster than calling isSelected() on all items in the same column and that unselectable items are ignored.

### bool QItemSelectionModel::isRowSelected ( int row, const QModelIndex & parent ) const

Returns true if all items are selected in the row with the given parent.

Note that this function is usually faster than calling isSelected() on all items in the same row and that unselectable items are ignored.

### bool QItemSelectionModel::isSelected ( const QModelIndex & index ) const

Returns true if the given model item index is selected.

### const QAbstractItemModel * QItemSelectionModel::model () const

Returns the item model operated on by the selection model.

### void QItemSelectionModel::reset () `[virtual slot]`

Clears the selection model. Does not emit any signals.

### bool QItemSelectionModel::rowIntersectsSelection ( int row, const QModelIndex & parent ) const

Returns true if there are any items selected in the row with the given parent.

### void QItemSelectionModel::select ( const QModelIndex & index, QItemSelectionModel::SelectionFlags command ) `[virtual slot]`

### void QItemSelectionModel::select ( const QItemSelection & selection, QItemSelectionModel::SelectionFlags command ) `[virtual slot]`

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

### QModelIndexList QItemSelectionModel::selectedIndexes () const

Returns a list of all selected model item indexes. The list contains no duplicates, and is not sorted.

### const QItemSelection QItemSelectionModel::selection () const

Returns the selection ranges stored in the selection model.

### void QItemSelectionModel::selectionChanged ( const QItemSelection & selected, const QItemSelection & deselected ) `[signal]`

This signal is emitted whenever the selection changes. The change in the selection is represented as an item selection of deselected items and an item selection of selected items.

See also select().

### void QItemSelectionModel::setCurrentIndex ( const QModelIndex & index, QItemSelectionModel::SelectionFlags command ) `[slot]`

See also currentIndex().