---
title: SignificantClassExtensions
summary: API reference for SignificantClassExtensions.
status: draft
owner: Technical Writer
last_reviewed: 2026-07-31
library: SAIF.Business.Policy.Group
reference_type: package
---

# SignificantClassExtensions

Provides in-memory filters for policy-period, included-class, and excluded-class views.

## Purpose
- Provides in-memory filters for policy-period, included-class, and excluded-class views.

## Context
- Namespace: `SAIF.Business.Policy.Group`
- Assembly/package: `SAIF.Business.Policy.Group`

## Public members
| Member | Signature | Purpose |
| --- | --- | --- |
| PerPolicyPeriod | `Public Function PerPolicyPeriod(ByVal Target As IEnumerable(Of clsSignificantClass), ByVal inPolicyPeriodEffectiveDate As Date) As IEnumerable(Of clsSignificantClass)` | Filters significant classes to those effective for the supplied policy-period date ([BR-018](../../../../../business-rules.md#br-018-significant-class-is-period-effective)). |
| IncludedClasses | `Public Function IncludedClasses(ByVal Target As IEnumerable(Of clsSignificantClass)) As IEnumerable(Of clsSignificantClass)` | Returns only significant classes classified as included ([BR-020](../../../../../business-rules.md#br-020-significant-class-filters-follow-significance)). |
| ExcludedClasses | `Public Function ExcludedClasses(ByVal Target As IEnumerable(Of clsSignificantClass)) As IEnumerable(Of clsSignificantClass)` | Returns only significant classes classified as excluded ([BR-020](../../../../../business-rules.md#br-020-significant-class-filters-follow-significance)). |
| PerPolicyPeriod | `Public Function PerPolicyPeriod(ByVal Target As clsSignificantClassCollection, ByVal inPolicyPeriodEffectiveDate As Date) As IEnumerable(Of clsSignificantClass)` | Filters significant classes to those effective for the supplied policy-period date ([BR-018](../../../../../business-rules.md#br-018-significant-class-is-period-effective)). |
| IncludedClasses | `Public Function IncludedClasses(ByVal Target As clsSignificantClassCollection) As IEnumerable(Of clsSignificantClass)` | Returns only significant classes classified as included ([BR-020](../../../../../business-rules.md#br-020-significant-class-filters-follow-significance)). |
| ExcludedClasses | `Public Function ExcludedClasses(ByVal Target As clsSignificantClassCollection) As IEnumerable(Of clsSignificantClass)` | Returns only significant classes classified as excluded ([BR-020](../../../../../business-rules.md#br-020-significant-class-filters-follow-significance)). |


## Behavioral notes
- This type follows the BOF business-object or collection lifecycle exposed by its public surface.*

## Constraints and usage notes
- These methods operate on in-memory collections; callers must retrieve data before applying the extension filters.

> **Note:** Statements marked with * were inferred from code structure, naming conventions, or
> contextual evidence where direct confirmation was not available in source artifacts. Statements
> marked with ** could not be confirmed; treat as unknown until verified.

## Sources
- `Business\\SAIF.Business.Policy.Group\\clsSignificantClassCollection.vb`