Sets the expression that is evaluated to obtain numbers from items.
Unless an expression is set on @self, the sorter will always compare items as invalid.
The expression must have a return type that can be compared numerically, such as %G_TYPE_INT or %G_TYPE_DOUBLE.
a GtkExpression, or %NULL
See Implementation
Sets the expression that is evaluated to obtain numbers from items.
Unless an expression is set on @self, the sorter will always compare items as invalid.
The expression must have a return type that can be compared numerically, such as %G_TYPE_INT or %G_TYPE_DOUBLE.