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QIdentityProxyModel Class

The QIdentityProxyModel class proxies its source model unmodified More...

Header: #include <QIdentityProxyModel>
qmake: QT += core
Since: Qt 4.8
Inherits: QAbstractProxyModel

Public Functions

QIdentityProxyModel(QObject *parent = Q_NULLPTR)
~QIdentityProxyModel()

Reimplemented Public Functions

virtual int columnCount(const QModelIndex &parent = QModelIndex()) const
virtual bool dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent)
virtual QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const
virtual QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const
virtual bool insertColumns(int column, int count, const QModelIndex &parent = QModelIndex())
virtual bool insertRows(int row, int count, const QModelIndex &parent = QModelIndex())
virtual QModelIndex mapFromSource(const QModelIndex &sourceIndex) const
virtual QItemSelection mapSelectionFromSource(const QItemSelection &selection) const
virtual QItemSelection mapSelectionToSource(const QItemSelection &selection) const
virtual QModelIndex mapToSource(const QModelIndex &proxyIndex) const
virtual QModelIndexList match(const QModelIndex &start, int role, const QVariant &value, int hits = 1, Qt::MatchFlags flags = Qt::MatchFlags( Qt::MatchStartsWith | Qt::MatchWrap )) const
virtual QModelIndex parent(const QModelIndex &child) const
virtual bool removeColumns(int column, int count, const QModelIndex &parent = QModelIndex())
virtual bool removeRows(int row, int count, const QModelIndex &parent = QModelIndex())
virtual int rowCount(const QModelIndex &parent = QModelIndex()) const
virtual void setSourceModel(QAbstractItemModel *newSourceModel)
virtual QModelIndex sibling(int row, int column, const QModelIndex &idx) const

Additional Inherited Members

Detailed Description

The QIdentityProxyModel class proxies its source model unmodified

QIdentityProxyModel can be used to forward the structure of a source model exactly, with no sorting, filtering or other transformation. This is similar in concept to an identity matrix where A.I = A.

Because it does no sorting or filtering, this class is most suitable to proxy models which transform the data() of the source model. For example, a proxy model could be created to define the font used, or the background colour, or the tooltip etc. This removes the need to implement all data handling in the same class that creates the structure of the model, and can also be used to create re-usable components.

This also provides a way to change the data in the case where a source model is supplied by a third party which can not be modified.

class DateFormatProxyModel : public QIdentityProxyModel
{
  // ...

  void setDateFormatString(const QString &formatString)
  {
    m_formatString = formatString;
  }

  QVariant data(const QModelIndex &index, int role) const
  {
    if (role != Qt::DisplayRole)
      return QIdentityProxyModel::data(index, role);

    const QDateTime dateTime = sourceModel()->data(SourceClass::DateRole).toDateTime();

    return dateTime.toString(m_formatString);
  }

private:
  QString m_formatString;
};

See also QAbstractProxyModel, Model/View Programming, and QAbstractItemModel.

Member Function Documentation

QIdentityProxyModel::QIdentityProxyModel(QObject *parent = Q_NULLPTR)

Constructs an identity model with the given parent.

QIdentityProxyModel::~QIdentityProxyModel()

Destroys this identity model.

[virtual] int QIdentityProxyModel::columnCount(const QModelIndex &parent = QModelIndex()) const

Reimplemented from QAbstractItemModel::columnCount().

[virtual] bool QIdentityProxyModel::dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent)

Reimplemented from QAbstractItemModel::dropMimeData().

[virtual] QVariant QIdentityProxyModel::headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const

Reimplemented from QAbstractItemModel::headerData().

[virtual] QModelIndex QIdentityProxyModel::index(int row, int column, const QModelIndex &parent = QModelIndex()) const

Reimplemented from QAbstractItemModel::index().

[virtual] bool QIdentityProxyModel::insertColumns(int column, int count, const QModelIndex &parent = QModelIndex())

Reimplemented from QAbstractItemModel::insertColumns().

[virtual] bool QIdentityProxyModel::insertRows(int row, int count, const QModelIndex &parent = QModelIndex())

Reimplemented from QAbstractItemModel::insertRows().

[virtual] QModelIndex QIdentityProxyModel::mapFromSource(const QModelIndex &sourceIndex) const

Reimplemented from QAbstractProxyModel::mapFromSource().

[virtual] QItemSelection QIdentityProxyModel::mapSelectionFromSource(const QItemSelection &selection) const

Reimplemented from QAbstractProxyModel::mapSelectionFromSource().

[virtual] QItemSelection QIdentityProxyModel::mapSelectionToSource(const QItemSelection &selection) const

Reimplemented from QAbstractProxyModel::mapSelectionToSource().

[virtual] QModelIndex QIdentityProxyModel::mapToSource(const QModelIndex &proxyIndex) const

Reimplemented from QAbstractProxyModel::mapToSource().

[virtual] QModelIndexList QIdentityProxyModel::match(const QModelIndex &start, int role, const QVariant &value, int hits = 1, Qt::MatchFlags flags = Qt::MatchFlags( Qt::MatchStartsWith | Qt::MatchWrap )) const

Reimplemented from QAbstractItemModel::match().

[virtual] QModelIndex QIdentityProxyModel::parent(const QModelIndex &child) const

Reimplemented from QAbstractItemModel::parent().

[virtual] bool QIdentityProxyModel::removeColumns(int column, int count, const QModelIndex &parent = QModelIndex())

Reimplemented from QAbstractItemModel::removeColumns().

[virtual] bool QIdentityProxyModel::removeRows(int row, int count, const QModelIndex &parent = QModelIndex())

Reimplemented from QAbstractItemModel::removeRows().

[virtual] int QIdentityProxyModel::rowCount(const QModelIndex &parent = QModelIndex()) const

Reimplemented from QAbstractItemModel::rowCount().

[virtual] void QIdentityProxyModel::setSourceModel(QAbstractItemModel *newSourceModel)

Reimplemented from QAbstractProxyModel::setSourceModel().

[virtual] QModelIndex QIdentityProxyModel::sibling(int row, int column, const QModelIndex &idx) const

Reimplemented from QAbstractItemModel::sibling().

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