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Diffstat (limited to 'src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc')
| -rw-r--r-- | src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc b/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc index b506de471f..a5ad6af4a2 100644 --- a/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc +++ b/src/qml/doc/src/qmllanguageref/syntax/propertybinding.qdoc @@ -179,6 +179,26 @@ Rectangle { Now, after the space key is pressed, the rectangle's height will continue auto-updating to always be three times its width. +\section3 Debugging overwriting of bindings + +A common cause of bugs in QML applications is accidentally overwriting bindings +with static values from JavaScript statements. To help developers track down +problems of this kind, the QML engine is able to emit messages whenever a +binding is lost due to imperative assignments. + +In order to generate such messages, you need to enable the informational output +for the \c{qt.qml.binding.removal} logging category, for instance by calling: + +\code +QLoggingCategory::setFilterRules(QStringLiteral("qt.qml.binding.removal.info=true")); +\endcode + +Please refer to the QLoggingCategory documentation for more information about +enabling output from logging categories. + +Note that is perfectly reasonable in some circumstances to overwrite bindings. +Any message generated by the QML engine should be treated as a diagnostic aid, +and not necessarily as evidence of a problem without further investigation. \section2 Using \c this with Property Binding |