- Qt 6.9
- Qt Core
- C++ Classes
- QPropertyBindingError
- Qt 6.9.3 Reference Documentation

# QPropertyBindingError Class

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

- List of all members, including inherited members

## Public Types

enum | Type { NoError, BindingLoop, EvaluationError, UnknownError }

## Public Functions

| QPropertyBindingError()
| QPropertyBindingError(QPropertyBindingError::Type type, const QString &description = QString())
| QPropertyBindingError(const QPropertyBindingError &other)
| QPropertyBindingError(QPropertyBindingError &&other)
| ~QPropertyBindingError()
QString | description() const
QPropertyBindingError::Type | type() const
QPropertyBindingError & | operator=(QPropertyBindingError &&other)
QPropertyBindingError & | operator=(const QPropertyBindingError &other)

## Detailed Description

QPropertyBindingError is used by the property system to report errors that occurred when a binding was evaluated. Use type() to query which error occurred, and description() to extract an error message which might contain more details. If there is no error, QPropertyBindingError has type `QPropertyBindingError::NoError` and `hasError()` returns false.

     extern QProperty<int> prop;

     QPropertyBindingError error = prop.binding().error();
     if (error.hasError())
          qDebug() << error.description();

## Member Type Documentation

### enum QPropertyBindingError::Type

This enum specifies which error occurred.

Constant | Value | Description
--- | --- | ---
`QPropertyBindingError::NoError` | `0` | No error occurred while evaluating the binding.
`QPropertyBindingError::BindingLoop` | `1` | Binding evaluation was stopped because a property depended on its own value.
`QPropertyBindingError::EvaluationError` | `2` | Binding evaluation was stopped for any other reason than a binding loop. For example, this value is used in the QML engine when an exception occurs while a binding is evaluated.
`QPropertyBindingError::UnknownError` | `3` | A generic error type used when neither of the other values is suitable. Calling description() might provide details.

## Member Function Documentation

### QPropertyBindingError::QPropertyBindingError()

Default constructs QPropertyBindingError. hasError() will return false, type will return `NoError` and description() will return an empty string.

### QPropertyBindingError::QPropertyBindingError(QPropertyBindingError::Type type, const QString &description = QString())

Constructs a QPropertyBindingError of type type with description as its description.

### QPropertyBindingError::QPropertyBindingError(const QPropertyBindingError &other)

Copy-constructs QPropertyBindingError from other.

### QPropertyBindingError::QPropertyBindingError(QPropertyBindingError &&other)

Move-constructs QPropertyBindingError from other. other will be left in its default state.

### `[noexcept]` QPropertyBindingError::~QPropertyBindingError()

Destroys the QPropertyBindingError.

### QString QPropertyBindingError::description() const

Returns a descriptive error message for the QPropertyBindingError if it has been set.

### QPropertyBindingError::Type QPropertyBindingError::type() const

Returns the type of the QPropertyBindingError.

See also QPropertyBindingError::Type.

### QPropertyBindingError &QPropertyBindingError::operator=(QPropertyBindingError &&other)

Move-assigns other to this QPropertyBindingError. other will be left in its default state.

### QPropertyBindingError &QPropertyBindingError::operator=(const QPropertyBindingError &other)

Copies other to this QPropertyBindingError.