5.5.2.1.11. Send Event Action Node

Send Event Action Node

A Send Event Action Node constructs an event and sends it to a selected behavior. It represents an asynchronous communication step in an Activity; the outgoing flow continues after the send action completes. The target is selected as a BehaviorId.

sequenceDiagram
    participant Activity
    participant Target as Target behavior
    Activity->>Target: Send event
    Target-->>Activity: Event handling result
    Activity->>Activity: Continue outgoing flow

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Definition

Provide an event factory and a target selector. The selector may use the action context and input tokens to choose the recipient.

public sealed record ShipmentReady(string OrderId);

The following fragment belongs inside the relevant method or builder callback:

.AddSendEventAction<ShipmentReady>(
    "NotifyShipping",
    async c => new ShipmentReady(
        c.GetTokensOfType<string>().Single()),
    async c => new BehaviorId(
        "StateMachine", "Shipping", "shipping-default"),
    node => node.AddControlFlow("Continue"))
.AddAction("Continue", async c =>
    await audit.RecordAsync("shipping-notified", c.CancellationToken))

The action looks up the selected behavior and awaits SendAsync if it is locatable. If it is not locatable, the current implementation skips the send; it does not synthesize a local token or turn that miss into an action exception. Ensure the target is discoverable when delivery is required. For receiving events, see Accept Event Action Node; for a notification that does not select a target behavior, see Publish Event Action Node.