改变已计划任务的运行时间在Windows任务调度程序

我有问题，修改已经存在计算机上的任务。我想从C＃中产生的互操作接口（从SYSTEM32 / taskschd.dll产生Interop.TaskScheduler.dll）做到这一点。

I have problem with modifying tasks which already exists on machine. I'm trying to do this with generated interop interfaces from C# (Interop.TaskScheduler.dll generated from system32/taskschd.dll).

首先，我不能用到其他库一样的 http://taskscheduler.codeplex.com/ 。
已经测试过，并与前面提到的图书馆工作。现在，当我尝试做同样与生成的接口没有任何变化。基本上我在做什么：

To start with, I can't use other libraries like http://taskscheduler.codeplex.com/. Already tested and it works with library mentioned before. Now when I try do same with generated interfaces nothing changes. Basically what I'm doing:

string STR_DateTimeFormat = "yyyy-MM-dd HH:mm:ss";
string taskName = "taskName", 
       user = "user", 
       pass = "pass";

DateTime nextRun = new DateTime.Now.AddDays(7);

TaskSchedulerClass ts = new TaskSchedulerClass();
ts.Connect(null, null, null, null);
IRegisteredTask task = ts.GetFolder("\\").GetTask(String.Format("\\{0}",taskName));

foreach (ITrigger t in task.Definition.Triggers)
    t.StartBoundary = nextRun.ToString(STR_DateTimeFormat.Replace(" ", "T"));

ts.GetFolder("\\").RegisterTaskDefinition(task.Path, 
                            task.Definition, 
                            (int)_TASK_CREATION.TASK_UPDATE, 
                            user, 
                            pass, 
                            _TASK_LOGON_TYPE.TASK_LOGON_PASSWORD, 
                            null);

有关它应该是工作先来看看，但由于某些原因，当我尝试分配为运行新的datetime在行：

For first look it should be working, but for some reason when I try to assign new datetime for run in line:

t.StartBoundary = nextRun.ToString(STR_DateTimeFormat.Replace(" ", "T"));

这是行不通的。其实在这的foreach它改变了，但是当我试图调试，并创建了另一个的foreach它打印的价值StartBoundary它显示了旧值。我做得不正确的？是否有机会得到它的工作？ :-)谢谢你。

It doesn't work. Actually in that foreach it's changed but when I tried to debug and created another foreach which prints value of StartBoundary it shows old value. Am I doing something incorrect? Is there any chance to get it working? :-) Thank you.