Service activity that implements an operation defined by a Windows Communication Foundation (WCF) service contract.
Assembly: System.WorkflowServices (in System.WorkflowServices.dll)
The activity is used when a workflow implements an operation defined in a WCF service contract. The can implement an operation from an already defined service contract or can define the service contract and operation within the workflow itself. The latter is known as a workflow-first contract.
The activity supports a set of predefined message exchange patterns. These patterns include:
The client that sends the message does not expect the service to send a response. The contract operation should have a void return type.
Receive request - Send response
After a message is received and processed by the activity, a response is sent back to the client. When the contract operation has a void return type, an acknowledgement is sent back to the send activity.
Receive request - Send fault
After a message is received and processed by the activity, a response or a fault is sent back to the client.
To ensure that persistence performs properly and does not persist transient messages, make sure that child activities of the do not persist by themselves. This can occur if the child activities go idle when a persistence provider was created with UnloadOnIdle set to true, for instance.