Constraints form - Completing the Pages & Classes tab

Complete this tab to list the pages referenced by name in the Constraints tab, and to identify the context of the properties constrained. You can reference locatable pages in constraints rules.

For basic instructions, see How to Complete a Pages & Classes tab.

Field	Description
Page Name	Optional. Identify a page that is the source of properties referenced on the Constraints tab. For a locatable page, enter the keyword `locate` followed by a page name. Optionally, add a row with the keyword `Top` as the page name, to identify a top-level page. The Top keyword allows you to use the syntax Top.propertyref to identify properties, on other tabs of this rule form.
Class	Optional. Select the class of that page.
Locate Page Expression	Optional. To use an activity to locate a locatable page, enter a Boolean expression here. If this evaluates to true, the system uses the activity identified in the Locate Page Activity field to find and temporarily add the page to your clipboard. Typically, enter an expression that evaluates to false when the page corresponding to the entry in the Page Name field is already present on the clipboard and contains the needed properties. For guided entry of any expression, click the Open icon. or the Open expression builder icon to start the Expression Builder.
Locate Page Activity	Optional. Enter the second key part — Activity Name — of an activity type `Locate` that can find the page identified in this row. If the activity has parameters, click the Get Locate Activity Params button to enter values for the parameters. The system uses the Applies To key part of this constraints rule as the first key part of the activity.
Page Context Data
Page Context	Optional. Leave this blank if the constrained property or properties (on the Constraints tab) all have mode `Single Value`. Otherwise, identify a `Page List` or `Page Group` property on the clipboard. You can supply literal index (subscript) values or property-reference index values. Precede the property reference with a period. To indicate that all the values of the index are acceptable, omit any index between parentheses. For example, these are acceptable: `Invoices.py Orders(2).pyItems("Manuals").pyItems` `Invoices.py Orders().pyItems().pyItemNames`
Page Class	Optional. If the Page Context field is not blank, identify the class of the page or pages that are identified in the Page Context field. (You cannot use the `$ANY`, `$NONE` or `$CLASS` keywords here.)

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