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Child Workflows - .NET SDK feature guide

This page shows how to do the following:

Start a Child Workflow Execution​

How to start a Child Workflow Execution using the Temporal .NET SDK

A Child Workflow Execution is a Workflow Execution that is scheduled from within another Workflow using a Child Workflow API.

When using a Child Workflow API, Child Workflow related Events (StartChildWorkflowExecutionInitiated, ChildWorkflowExecutionStarted, ChildWorkflowExecutionCompleted, etc...) are logged in the Workflow Execution Event History.

Always block progress until the ChildWorkflowExecutionStarted Event is logged to the Event History to ensure the Child Workflow Execution has started. After that, Child Workflow Executions may be abandoned using the default Abandon Parent Close Policy set in the Child Workflow Options.

To spawn a Child Workflow Execution in .NET, use the ExecuteChildWorkflowAsync() method which starts the Child Workflow and waits for completion or use the StartChildWorkflowAsync() method to start a Child Workflow and return its handle. This is useful if you want to do something after it has only started, or to get the Workflow/Run ID, or to be able to signal it while running.

note

ExecuteChildWorkflowAsync() is a helper method for StartChildWorkflowAsync() plus await handle.GetResultAsync().

await Workflow.ExecuteChildWorkflowAsync((MyChildWorkflow wf) => wf.RunAsync());

Set a Parent Close Policy​

How to set a Parent Close Policy using the Temporal .NET SDK

A Parent Close Policy determines what happens to a Child Workflow Execution if its Parent changes to a Closed status (Completed, Failed, or Timed Out).

The default Parent Close Policy option is set to terminate the Child Workflow Execution.

Set the ParentClosePolicy property inside the ChildWorkflowOptions for ExecuteChildWorkflowAsync or StartChildWorkflowAsync to specify the behavior of the Child Workflow when the Parent Workflow closes.

await Workflow.ExecuteChildWorkflowAsync(
  (MyChildWorkflow wf) => wf.RunAsync(),
  new() { ParentClosePolicy = ParentClosePolicy.Abandon });