Filter Methods

The following methods control Named Filter objects. A Named Filter is an object which has rules which it uses to "pass" some items but "fail" others.

Named Filter objects can be applied to overlays to control the visibility of the items in that overlay: only items which pass are drawn, all other items become temporarily invisible.

In addition, many SIS Desktop methods, e.g. Scan, accept a Named Filter as an argument.

There are several different types of Named Filter, which have different rules: see Filters for details.

Named Filter objects can be saved in, and loaded from, Named Object Libraries. Named Filter objects can be created, edited and set using the methods below.

ChangeFeatureFilter	Modifies feature code information in a named feature filter.
ChangeValueListFilter	Changes the values included in a named value-list filter.
CombineFilter	Creates a named filter by combining two named filters using a Boolean operation.
CreateClassTreeFilter	Creates a named class tree filter.
CreateCombinedFilter	Creates a named combined class/property filter.
CreateFeatureFilter	Creates a named feature filter based on a named feature table.
CreateLayerFilter	Creates a named layer filter.
CreateLinkFilter	Creates an empty named link filter.
CreatePropertyFilter	Creates a named property filter.
CreateValueListFilter	Creates an empty named value-list filter.
GetClassTreeFilterValues	Returns a space-separated list of all of the classes in a named class tree filter, prefixed with a '+' or '-' to indicate inclusion and exclusion.
GetFeatureFilterBranches	Gets the feature codes branching from a parent feature code in a named feature filter.
GetFeatureFilterCodes	Returns a space-separated list of all of the feature codes in a named feature filter, prefixed with a '+' or '-' to indicate inclusion and exclusion.
GetFeatureFilterTable	Finds a feature table in a NOL that matches the one stored in a feature filter.
GetFilterClass	Returns the class of a named filter.
GetLayerFilterValues	Returns a tab-separated list of all of the layers in a named layer filter, prefixed with a '+' or '-' to indicate inclusion and exclusion.
GetLinkFilterIds	Returns a space-separated list of values from a named link filter.
GetOverlayFilter	Gets a copy of an overlay drawing filter.
GetPropertyFilterFormula	Returns the expression of a named property filter.
GetValueListFilterProperty	Returns the property used by a named value list filter.
GetValueListFilterValues	Returns a space-separated list of values from a named value list filter.
SetCombinedFilterClause	Adds a clause to a named combined class/property filter.
SetOverlayFilter	Applies a copy of a named filter to an overlay in the current SWD.
SplitCombinedFilter	Splits a named combined filter in two new named filters, and returns the combine Boolean operation.

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