Validation functions

The syntax for the Filter Expression and Test Expression formulae are the same as for ShapeSheet formulae. However, Visio 2010 includes some extra validation functions that are like ShapeSheet functions, but cannot be used in ShapeSheet formulae.

The following table is an extract from The Diagram Validation API blog that can be found at: http://blogs.msdn.com/visio/archive/2010/01/07/the-diagram-validation-api.aspx

It lists the special quasi-ShapeSheet functions that can be used in the Filter Expression and Test Expression formulae.

Function	Description
Role()	Returns an integer indicating the shape role: (Element = 0, Connector = 1, Container = 2, Callout = 4).
OnLayer(LayerName)	Returns a Boolean indicating whether the shape is a member of the specified layer. Returns a Boolean indicating whether layer exists on the page, if called on a page.
ConnectedShapes(Direction)	Returns the set of shapes, matching the Direction criteria, connected to the shape...