Difference between revisions of "Candidate Tag Expression"
| Line 4: | Line 4: | ||
The Candidate tag expression is always applied against the pick/thing itself. The tag expression is compared against all of the tags possessed by the object. For picks, this includes the effects of all dynamically assigned and deleted tags. The Candidate tag expression is only invoked when the user triggers the portal to display the list of options to choose from. Consequently, the tags used for picks are the final set of tags after evaluation completes. This also means that picks can dynamically change their state and change whether they appear as valid choices within a given portal. | The Candidate tag expression is always applied against the pick/thing itself. The tag expression is compared against all of the tags possessed by the object. For picks, this includes the effects of all dynamically assigned and deleted tags. The Candidate tag expression is only invoked when the user triggers the portal to display the list of options to choose from. Consequently, the tags used for picks are the final set of tags after evaluation completes. This also means that picks can dynamically change their state and change whether they appear as valid choices within a given portal. | ||
| + | |||
| + | When a Candidate tag expression is used in conjunction with a List tag expression, the two are always considered additive. Objects included in the selection list must satisfy the '''both''' the Candidate tag expression '''and''' the List tag expression. This ensures that items shown for selection are always able to be viewed within portal, allowing them to be deleted appropriately if the user changes his mind. | ||
Revision as of 03:23, 7 December 2008
Context: HL Kit … Kit Reference … Tag Expression Types
The role of the Candidate tag expression is to determine whether a pick or thing should be included in a choose form. The choose form contains the list of picks/things from which the user can select when adding items to a portal (i.e. dynamic table, chooser, or thing-based menu). If the tag expression is satisfied, then the pick/thing is shown within the list of options and can be added by the user. Otherwise, the pick/thing is omitted from the available list.
The Candidate tag expression is always applied against the pick/thing itself. The tag expression is compared against all of the tags possessed by the object. For picks, this includes the effects of all dynamically assigned and deleted tags. The Candidate tag expression is only invoked when the user triggers the portal to display the list of options to choose from. Consequently, the tags used for picks are the final set of tags after evaluation completes. This also means that picks can dynamically change their state and change whether they appear as valid choices within a given portal.
When a Candidate tag expression is used in conjunction with a List tag expression, the two are always considered additive. Objects included in the selection list must satisfy the both the Candidate tag expression and the List tag expression. This ensures that items shown for selection are always able to be viewed within portal, allowing them to be deleted appropriately if the user changes his mind.
