订阅流程类型的事件，然后在回调方法里面进行流程变量的读取或者操作。

//start a new process instance

IWorkflowService wfService = new WorkflowService();

var wfResult = wfService.CreateRunner(runner.UserID, runner.UserName)

         .UseApp(runner.AppInstanceID, runner.AppName, runner.AppInstanceCode)

         .UseProcess(runner.ProcessGUID, runner.Version)

         .Subscribe(EventFireTypeEnum.OnProcessStarted, (delegateContext, delegateService) => {

         var processInstanceID = delegateContext.ProcessInstanceID;                             delegateService.SaveVariable(ProcessVariableTypeEnum.Process, "name", "book");                             delegateService.SaveVariable(ProcessVariableTypeEnum.Process, "amount", "30");

         return true;

})

         .Start();