You need to assign an event to the transition in order to specify an occurrence of an event which can trigger a state transition.

You can assign an event type to a transition in the following ways:

  • Using the transition’s Specification window.
  • By typing an appropriate command straight on the selected transition path.


To assign an event type in the Transition Specification window

  1. Open the transition’s Specification window.

  2. In the Trigger category, select the Event Type property value cell. The list of available event types opens.

  3. Select the event type from the list. According to the selected event type, Event Element, and Trigger property values are defined and additional corresponding properties appears in the Trigger category (see the following figure).

  4. Click the Close button after you have defined desired properties.

Trigger category before assigning event type (on the left) and after assigning event type (on the right)


To assign an event type straight on a transition path

  1. Select a transition path on the diagram pane.
  2. Type the command of the appropriate event type. The event type is assigned to the transition. In the following figure, see an example of the signal event type assignment.

Example of signal event, that was specified typing text straight on transition

See the list with the event type and its command syntax in the following table.

NameCommand syntax
Any Receive Eventall
Call Event

<operation name ()>
NOTE: Before assigning operation straight on the transition path the Call Event together with this operation should be already created in the same State Machine as the transition.

Change Eventwhen (<expression>)
Signal Event<signal name>
Time Event
  • after (<time>) - for an event occurring at a relative time
  • at (<time>) - for an event occurring at an absolute time

The event type assigning by typing the command straight on the diagram pane is also available for a transition to self in the State Machine diagram, as well as for a protocol transition and protocol transition to self in the Protocol State Machine diagram.

Related pages