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ExpressionSorter

Sorts row with a custom sorting. More...

Import Statement: import Felgo 3.0
Since: Felgo 2.18.1
Inherits:

Sorter

Properties

Detailed Description

An ExpressionSorter is a Sorter allowing to implement custom sorting based on a javascript expression.

Property Documentation

expression : expression

An expression to implement custom sorting. It must evaluate to a bool. It has the same syntax has a Property Binding, except that it will be evaluated for each of the source model's rows. Model data is accessible for both rows with the modelLeft, and modelRight properties:

 sorters: ExpressionSorter {
     expression: {
         return modelLeft.someRole < modelRight.someRole;
     }
 }

The index of the row is also available through modelLeft and modelRight.

The expression should return true if the value of the left item is less than the value of the right item, otherwise returns false.

This expression is re-evaluated for a row every time its model data changes. When an external property (not index* or in model*) the expression depends on changes, the expression is re-evaluated for every row of the source model. To capture the properties the expression depends on, the expression is first executed with invalid data and each property access is detected by the QML engine. This means that if a property is not accessed because of a conditional, it won't be captured and the expression won't be re-evaluated when this property changes.

A workaround to this problem is to access all the properties the expressions depends unconditionally at the beginning of the expression.