- Qt 6.8
- Qt Widgets Designer Manual
- C++ Classes
- QDesignerPropertyEditorInterface
- Qt 6.8.0 Reference Documentation

# QDesignerPropertyEditorInterface Class

The QDesignerPropertyEditorInterface class allows you to query and manipulate the current state of Qt Widgets Designer's property editor. More...

Header: | `#include <QDesignerPropertyEditorInterface>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Designer)` `target_link_libraries(mytarget PRIVATE Qt6::Designer)`
qmake: | `QT += designer`

- List of all members, including inherited members

## Public Functions

| QDesignerPropertyEditorInterface(QWidget *parent, Qt::WindowFlags flags = {})
virtual | ~QDesignerPropertyEditorInterface()
virtual QDesignerFormEditorInterface * | core() const
virtual QString | currentPropertyName() const = 0
virtual bool | isReadOnly() const = 0
virtual QObject * | object() const = 0

## Public Slots

virtual void | setObject(QObject *object) = 0
virtual void | setPropertyValue(const QString &name, const QVariant &value, bool changed = true) = 0
virtual void | setReadOnly(bool readOnly) = 0

## Signals

void | propertyChanged(const QString &name, const QVariant &value)

## Detailed Description

QDesignerPropertyEditorInterface contains a collection of functions that is typically used to query the property editor for its current state, and several slots manipulating it's state. The interface also provide a signal, propertyChanged(), which is emitted whenever a property changes in the property editor. The signal's arguments are the property that changed and its new value.

For example, when implementing a custom widget plugin, you can connect the signal to a custom slot:

             auto *propertyEditor = formEditor->propertyEditor();

             connect(propertyEditor, &QDesignerPropertyEditorInterface::propertyChanged,
                     this, &MyClass::checkProperty);

Then the custom slot can check if the new value is within the range we want when a specified property, belonging to a particular widget, changes:

             void checkProperty(const QString &property, const QVariant &value)
             {
                 auto *propertyEditor = formEditor->propertyEditor();

                 auto *object = propertyeditor->object();
                 auto *widget = qobject_cast<MyCustomWidget *>(object);

                 if (widget && property == aProperty && value != expectedValue)
                     {...}
             }

The QDesignerPropertyEditorInterface class is not intended to be instantiated directly. You can retrieve an interface to Qt Widgets Designer's property editor using the QDesignerFormEditorInterface::propertyEditor() function. A pointer to Qt Widgets Designer's current QDesignerFormEditorInterface object (`formEditor` in the examples above) is provided by the QDesignerCustomWidgetInterface::initialize() function's parameter. When implementing a custom widget plugin, you must subclass the QDesignerCustomWidgetInterface to expose your plugin to Qt Widgets Designer.

The functions accessing the property editor are the core() function that you can use to retrieve an interface to the form editor, the currentPropertyName() function that returns the name of the currently selected property in the property editor, the object() function that returns the currently selected object in Qt Widgets Designer's workspace, and the isReadOnly() function that returns true if the property editor is write proteced (otherwise false).

The slots manipulating the property editor's state are the setObject() slot that you can use to change the currently selected object in Qt Widgets Designer's workspace, the setPropertyValue() slot that changes the value of a given property and the setReadOnly() slot that control the write protection of the property editor.

See also QDesignerFormEditorInterface.

## Member Function Documentation

### `[explicit]` QDesignerPropertyEditorInterface::QDesignerPropertyEditorInterface(QWidget *parent, Qt::WindowFlags flags = {})

Constructs a property editor interface with the given parent and the specified window flags.

### `[virtual noexcept]` QDesignerPropertyEditorInterface::~QDesignerPropertyEditorInterface()

Destroys the property editor interface.

### `[virtual]` QDesignerFormEditorInterface *QDesignerPropertyEditorInterface::core() const

Returns a pointer to Qt Widgets Designer's current QDesignerFormEditorInterface object.

### `[pure virtual]` QString QDesignerPropertyEditorInterface::currentPropertyName() const

Returns the name of the currently selected property in the property editor.

See also setPropertyValue().

### `[pure virtual]` bool QDesignerPropertyEditorInterface::isReadOnly() const

Returns true if the property editor is write protected; otherwise false.

See also setReadOnly().

### `[pure virtual]` QObject *QDesignerPropertyEditorInterface::object() const

Returns the currently selected object in Qt Widgets Designer's workspace.

See also setObject().

### `[signal]` void QDesignerPropertyEditorInterface::propertyChanged(const QString &name, const QVariant &value)

This signal is emitted whenever a property changes in the property editor. The property that changed and its new value are specified by name and value respectively.

See also setPropertyValue().

### `[pure virtual slot]` void QDesignerPropertyEditorInterface::setObject(QObject *object)

Changes the currently selected object in Qt Widgets Designer's workspace, to object.

See also object().

### `[pure virtual slot]` void QDesignerPropertyEditorInterface::setPropertyValue(const QString &name, const QVariant &value, bool changed = true)

Sets the value of the property specified by name to value.

In addition, the property is marked as changed in the property editor, i.e. its value is different from the default value.

See also currentPropertyName() and propertyChanged().

### `[pure virtual slot]` void QDesignerPropertyEditorInterface::setReadOnly(bool readOnly)

If readOnly is true, the property editor is made write protected; otherwise the write protection is removed.

See also isReadOnly().