Class: QgsExpressionContextGenerator

class qgis.core.QgsExpressionContextGenerator

Bases: sip.wrapper

Abstract interface for generating an expression context.

You need to implement this interface in a class and register this class with QgsFieldExpressionWidget.registerExpressionGenerator()

This is used for example in QgsPropertyOverrideButton or QgsFieldExpressionWidget classes which will ask for a new QgsExpressionContext every time the expression editor is opened. This way they are able to provide an up-to-date expression editor even when the environment changes.

New in version 3.0: Methods

createExpressionContext This method needs to be reimplemented in all classes which implement this interface and return an expression context.

Signals

Attributes

createExpressionContext(self) → QgsExpressionContext

This method needs to be reimplemented in all classes which implement this interface and return an expression context.

New in version 3.0.