QModelRoleData Class

The QModelRoleData class holds a role and the data associated to that role. More...

Header: #include <QModelRoleData>
CMake: find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core)
qmake: QT += core
Since: Qt 6.0

Public Functions

QModelRoleData(int role)
void clearData()
QVariant &data()
const QVariant &data() const
int role() const
void setData(T &&value)

Detailed Description

QModelRoleData objects store an item role (which is a value from the Qt::ItemDataRole enumeration, or an arbitrary integer for a custom role) as well as the data associated with that role.

A QModelRoleData object is typically created by views or delegates, setting which role they want to fetch the data for. The object is then passed to models (see QAbstractItemModel::multiData()), which populate the data corresponding to the role stored. Finally, the view visualizes the data retrieved from the model.

See also Model/View Programming and QModelRoleDataSpan.

Member Function Documentation

[explicit noexcept] QModelRoleData::QModelRoleData(int role)

Constructs a QModelRoleData object for the given role.

See also Qt::ItemDataRole.

[noexcept] void QModelRoleData::clearData()

Clears the data held by this object. Note that the role is unchanged; only the data is cleared.

See also data().

[constexpr noexcept] QVariant &QModelRoleData::data()

Returns the data held by this object as a modifiable reference.

See also setData().

[constexpr noexcept] const QVariant &QModelRoleData::data() const

Returns the data held by this object.

See also setData().

[constexpr noexcept] int QModelRoleData::role() const

Returns the role held by this object.

See also Qt::ItemDataRole.

[constexpr noexcept(...)] template <typename T> void QModelRoleData::setData(T &&value)

Sets the data held by this object to value. value must be of a datatype which can be stored in a QVariant.

Note: This function does not throw any exception when "noexcept(m_data.setValue(std::forward<T>(value)))" is true.

See also data(), clearData(), and Q_DECLARE_METATYPE.

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