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.

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.

Return type

QgsExpressionContext