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Diffstat (limited to 'src/corelib/doc')
| -rw-r--r-- | src/corelib/doc/src/objectmodel/bindableproperties.qdoc | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/corelib/doc/src/objectmodel/bindableproperties.qdoc b/src/corelib/doc/src/objectmodel/bindableproperties.qdoc index f0f16aeafe..75cc6f67d5 100644 --- a/src/corelib/doc/src/objectmodel/bindableproperties.qdoc +++ b/src/corelib/doc/src/objectmodel/bindableproperties.qdoc @@ -86,6 +86,36 @@ is an integer and folded into the string value using conversion to integer, but the dependency is fully tracked. + \section1 Bindable Property Getters and Setters + + When a class has a bindable property, either using QProperty + or QObjectBindableProperty, special care has to be taken when formulating + getters and setters for that property. + + \section2 Bindable Property Getters + + To ensure proper operation of the automatic dependency-tracking system, + every possible code path in a getter needs to read from the underlying + property object. + In addition, the property must not be written inside the getter. + Design patterns which recompute or refresh anything in the getter + are not compatible with bindable properties. + + It is therefore recommended to only use trivial getters with bindable properties. + + \section2 Bindable Property Setters + + To ensure proper operation of the automatic dependency-tracking system, + every possible code path in a setter needs to write to the underlying + property object, even if the value did not change. + + Any other code in a setter has a high propability of being incorrect. + Any code doing updates based on the new value is most likely a bug, + as this code won't be executed when the property is changed + through a binding. + + It is therefore recommended to only use trivial setters with bindable properties. + \section1 Tracking Bindable Properties Sometimes the relationships between properties cannot be expressed using |