The declarative rule conditions we've seen in the previous sections only return a value of true or false. A condition doesn't modify a workflow. A rule, on the other hand, is both a condition and a set of actions in an if-then-else form. The Rule
class in Windows Workflow represents this if-then-else concept. The class diagram in the following screenshot displays classes with important relationships to the Rule
class.
The first concept to notice is that the RuleSet
class manages a collection of rules. The Policy
activity will use the Execute
method of a RuleSet
to process the rule collection. We will cover the Policy
activity in more detail soon.
Every Rule
inside a RuleSet
has a Condition
property that references a single RuleCondition
object. The RuleSet
logic will use the Evaluate
method of a RuleCondition
to retrieve a value of true or false.
Every Rule
maintains two collections of RuleAction
objects—the ElseActions
and the ThenActions
. When a rule's condition evaluates...