After an enumeration is defined and assigned to an attribute, its labels are displayed in selection drop-down lists in both Conditions and Actions expressions, as shown. If Labels are not available (because Labels are optional in an enumerated custom data type's definition), then Values are shown. The null option in the drop-down list is only available if the attribute's Mandatory property value is set to No.

Figure 1. Using Custom Data Types in the Rulesheet

You can test a condition bound to an attribute by evaluating the attribute against a custom data type label using the # tag, as shown:

Figure 2. Using # tag to test a custom data type
Note: Using a dot instead of a # tag works, but if there is custom data type with the same name as an entity, then the expression will be invalid.