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Diffstat (limited to 'src/qml/doc/src/cppintegration/contextproperties.qdoc')
| -rw-r--r-- | src/qml/doc/src/cppintegration/contextproperties.qdoc | 45 |
1 files changed, 19 insertions, 26 deletions
diff --git a/src/qml/doc/src/cppintegration/contextproperties.qdoc b/src/qml/doc/src/cppintegration/contextproperties.qdoc index 869e01c69e..1783c0cdc8 100644 --- a/src/qml/doc/src/cppintegration/contextproperties.qdoc +++ b/src/qml/doc/src/cppintegration/contextproperties.qdoc @@ -1,34 +1,27 @@ -/**************************************************************************** -** -** Copyright (C) 2017 The Qt Company Ltd. -** Contact: https://www.qt.io/licensing/ -** -** This file is part of the documentation of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:FDL$ -** Commercial License Usage -** Licensees holding valid commercial Qt licenses may use this file in -** accordance with the commercial license agreement provided with the -** Software or, alternatively, in accordance with the terms contained in -** a written agreement between you and The Qt Company. For licensing terms -** and conditions see https://www.qt.io/terms-conditions. For further -** information use the contact form at https://www.qt.io/contact-us. -** -** GNU Free Documentation License Usage -** Alternatively, this file may be used under the terms of the GNU Free -** Documentation License version 1.3 as published by the Free Software -** Foundation and appearing in the file included in the packaging of -** this file. Please review the following information to ensure -** the GNU Free Documentation License version 1.3 requirements -** will be met: https://www.gnu.org/licenses/fdl-1.3.html. -** $QT_END_LICENSE$ -** -****************************************************************************/ +// Copyright (C) 2017 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only /*! \page qtqml-cppintegration-contextproperties.html \title Embedding C++ Objects into QML with Context Properties \brief Description of how to embed C++ data into QML using context properties +\warning By using context properties in your QML code, you create a dependency from your QML code + to the specific context you have in mind when writing it. This limits re-usability of your + code since the context may be different in other places where it might be used. + Furthermore, the dependency is not declared. You never \c import the context or otherwise + state what you expect. Therefore, anyone trying to re-use your code will have difficulties + finding out whether the place of re-use has a context sufficient for your code. + +\warning Context properties are invisible to any tooling that processes QML code ahead of time, + before you load it into the QML engine. The \l{Qt Quick Compiler}, + \l{qmllint Reference}{qmllint}, and the \l{\QMLLS Reference}{\QMLLS} do + not know anything about your context properties and will consider any access to context + properties as an \e{unqualified access}. + +\note Context properties can generally be replaced either by regular properties on the root object + of a component, or by singletons defined either in C++ using \l{QML_SINGLETON}{QML_SINGLETON} + or in QML using \l{Structure of a QML Document#Singleton}{pragma Singleton}. + When loading a QML object into a C++ application, it can be useful to directly embed some C++ data that can be used from within the QML code. This makes it possible, for example, to invoke a C++ method on the embedded object, or use a C++ object instance as a data model for a QML view. |