Qt 4.8: QItemSelection Class Reference

Qt Reference Documentation

# QItemSelection Class Reference

The QItemSelection class manages information about selected items in a model. More...

     #include <QItemSelection>

Inherits: QList<QItemSelectionRange>.

- List of all members, including inherited members

## Public Functions

| QItemSelection ()
| QItemSelection ( const QModelIndex & topLeft, const QModelIndex & bottomRight )
bool | contains ( const QModelIndex & index ) const
QModelIndexList | indexes () const
void | merge ( const QItemSelection & other, QItemSelectionModel::SelectionFlags command )
void | select ( const QModelIndex & topLeft, const QModelIndex & bottomRight )

- 67 public functions inherited from QList

## Static Public Members

void | split ( const QItemSelectionRange & range, const QItemSelectionRange & other, QItemSelection * result )

- 3 static public members inherited from QList

## Detailed Description

The QItemSelection class manages information about selected items in a model.

A QItemSelection describes the items in a model that have been selected by the user. A QItemSelection is basically a list of selection ranges, see QItemSelectionRange. It provides functions for creating and manipulating selections, and selecting a range of items from a model.

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

An item selection can be constructed and initialized to contain a range of items from an existing model. The following example constructs a selection that contains a range of items from the given `model`, beginning at the `topLeft`, and ending at the `bottomRight`.

     QItemSelection *selection = new QItemSelection(topLeft, bottomRight);

An empty item selection can be constructed, and later populated as required. So, if the model is going to be unavailable when we construct the item selection, we can rewrite the above code in the following way:

     QItemSelection *selection = new QItemSelection();
     ...
     selection->select(topLeft, bottomRight);

QItemSelection saves memory, and avoids unnecessary work, by working with selection ranges rather than recording the model item index for each item in the selection. Generally, an instance of this class will contain a list of non-overlapping selection ranges.

Use merge() to merge one item selection into another without making overlapping ranges. Use split() to split one selection range into smaller ranges based on a another selection range.

See also Model/View Programming and QItemSelectionModel.

## Member Function Documentation

### QItemSelection::QItemSelection ()

Constructs an empty selection.

### QItemSelection::QItemSelection ( const QModelIndex & topLeft, const QModelIndex & bottomRight )

Constructs an item selection that extends from the top-left model item, specified by the topLeft index, to the bottom-right item, specified by bottomRight.

### bool QItemSelection::contains ( const QModelIndex & index ) const

Returns true if the selection contains the given index; otherwise returns false.

### QModelIndexList QItemSelection::indexes () const

Returns a list of model indexes that correspond to the selected items.

### void QItemSelection::merge ( const QItemSelection & other, QItemSelectionModel::SelectionFlags command )

Merges the other selection with this QItemSelection using the command given. This method guarantees that no ranges are overlapping.

Note that only QItemSelectionModel::Select, QItemSelectionModel::Deselect, and QItemSelectionModel::Toggle are supported.

See also split().

### void QItemSelection::select ( const QModelIndex & topLeft, const QModelIndex & bottomRight )

Adds the items in the range that extends from the top-left model item, specified by the topLeft index, to the bottom-right item, specified by bottomRight to the list.

Note: topLeft and bottomRight must have the same parent.

### void QItemSelection::split ( const QItemSelectionRange & range, const QItemSelectionRange & other, QItemSelection * result )`[static]`

Splits the selection range using the selection other range. Removes all items in other from range and puts the result in result. This can be compared with the semantics of the subtract operation of a set.

See also merge().