递归调用 Windows 工作流

Question

我有一个工作流程，在某个时刻需要递归触发。

我似乎不知道该怎么做。

我尝试了以下代码，但上下文最终为空？

private void codeTriggerChildren_ExecuteCode(object sender, EventArgs e)
{
    ActivityExecutionContext context = sender as ActivityExecutionContext;
    //context is null here?!

    IStartWorkflow aWorkflow = context.GetService(typeof(ApprovalFlow)) as IStartWorkflow;

    Dictionary<string, object> parameters = new Dictionary<string, object>();
    parameters.Add("Parm1", "foo");
    parameters.Add("Parm2", "bar");

    Guid guid = aWorkflow.StartWorkflow(typeof(ApprovalFlow), parameters);
}

Answer 1

这里的主要问题是，本例中的发送者是 CodeActivity，而不是 ActivityExecutionContext。所以这段代码在第一个障碍处就失败了。

下面是一个自定义活动的示例，可以执行您想要的操作：-

public class RecurseApproval : Activity
{
    protected override ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)
    {
        IStartWorkflow aWorkflow = executionContext.GetService(typeof(IStartWorkflow)) as IStartWorkflow;

        Dictionary<string, object> parameters = new Dictionary<string, object>();
        parameters.Add("Param1", "Foo");
        parameters.Add("Param2", "bar");

        Guid guid = aWorkflow.StartWorkflow(typeof(ApprovalWorkflow), parameters);

        return ActivityExecutionStatus.Closed;

    }
}

请注意，GetService 获取 IStartWorkflow 类型。

Answer 2

您的发送者的类型为 CodeActivity 而不是 ActivityExecutionContext。您需要创建一个自定义活动并重写 Execute 方法，该方法将向您传递 ActivityExecutionContext。