工作流持久化的问题

Question

在状态机工作流，有这样一段代码：

public class CustomPersistanceService : SqlWorkflowPersistenceService
    {
        public CustomPersistanceService()
            : base(SqlHelper.ConnectionStringWorkflowPersistence, true, new TimeSpan(0, 10, 0), new TimeSpan(-1))
        {
            base.EnableRetries = true;
        }

               protected override void SaveWorkflowInstanceState(System.Workflow.ComponentModel.Activity rootActivity, bool unlock)
        {
            string currentStateActivityName = "";

                currentStateActivityName = ((StateMachineWorkflowActivity)rootActivity).CurrentStateName;
               ......其他的业务代码
        }

  }

 

在这段代码中 有时获取到的currentStateActivityName的值为空，即不能正确的获取到当前节点的名称，请问这个是怎么回事啊，谢谢！