read-only-property.qdoc

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// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
\page qmllint-warnings-and-errors-read-only-property.html
\ingroup qmllint-warnings-and-errors
 
\title Readonly Property
\brief A readonly property was written.
 
\section1 Cannot Assign To Read-Only Property
 
\section2 What happened?
A \l{Read-Only Properties}{read-only property} was written.
 
\section2 Why is this bad?
The QML engine will throw a Type Error when it sees the write to a read-only property.
 
\section2 Example
\qml
import QtQuick
 
Item {
    id: root
    readonly property int someNumber: 10
 
    Component.onCompleted: {
        someNumber = 20  // not ok: TypeError: Cannot assign to read-only property
    }
}
\endqml
You can fix this warning by removing the write to the read-only property, by writing to another
non-read-only property, or by removing the readonly modifier if the property should no longer be
considered constant.
 
\sa{Read-Only Properties}
*/