- Qt 6.9
- Qt Core
- C++ Classes
- QPropertyChangeHandler
- Qt 6.9.2 Reference Documentation

# QPropertyChangeHandler Class

template <typename Functor> class QPropertyChangeHandler

The QPropertyChangeHandler class controls the lifecycle of change callback installed on a QProperty. More...

Header: | `#include <QPropertyChangeHandler>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Core)` `target_link_libraries(mytarget PRIVATE Qt6::Core)`
qmake: | `QT += core`
Inherits: | QPropertyObserver

## Detailed Description

QPropertyChangeHandler<Functor> is created when registering a callback on a QProperty to listen to changes to the property's value, using QProperty::onValueChanged and QProperty::subscribe. As long as the change handler is alive, the callback remains installed.

A handler instance can be transferred between C++ scopes using move semantics.