Represents a rule that is called when a transaction is beginning in the model.
Assembly: Microsoft.VisualStudio.Modeling.Sdk (in Microsoft.VisualStudio.Modeling.Sdk.dll)
When a transaction is beginning in the model and you want to do something programmatically, you define a class derived from this class.
A RuleOnAttribute attribute placed on the class indicates what type of object the Rule works on and when the rule should occurr.
The rule is called when the specified type of transaction is beginning.