如果您尝试像这样使用 Task Scheduler C# API 更新任务，则需要声明一个新的 ITaskDefinition.如果您尝试更改现有定义然后重新注册，则不起作用.

If you are attempting to update a task using the Task Scheduler C# API like this, you need to declare a new ITaskDefinition. If you attempt to change the existing definition and then re-Register, it does not work.

IRegisteredTask oldTask = ...
ITaskDefinition task = oldTask.Definition;

//modifications to oldTask.Definition / task

//does **not** work
folder.RegisterTaskDefinition(oldTask.Name, oldTask.Definition, ...
//does work
folder.RegisterTaskDefinition(oldTask.Name, task, ...

答案归于原始海报，请参阅问题评论.我写了这个答案来澄清这个问题，并提请注意这个问题已经得到回答，因为类似的问题困扰了我几天.

Answer credit goes to original poster, see comment on question. I wrote up this answer to clarify the issue, and draw attention to the fact that the question had been answered, as a similar issue troubled me for a few days.