There is a help file included with the download that provides an overview of the various classes. The
Microsoft MSDN documentation provides an excellent overview of the Task Scheduler along with details around security and permission, idle conditions, and trigger repetition.
- The Examples Page shows some C# code that demonstrates almost every function of the library.
- The Installation Page explains how to use this library in your own projects and includes a sample project.
The
TaskService class represents the machine specific instance of the system task scheduler. It provides access to information about the service, access folders (2.0 only), and can quickly add or retrieve a task. If you only need to use the library for very intermitant periods, wrap the TaskService instantiation in a
using statement to easily disconnect at the end of your use. However, if you plan on using the connection to the Task Scheduler repeatedly, use an assembly level field to store the TaskService instance as connecting and disconnecting is an expensive operation.
Tasks are accessed and can be enumerated through a
TaskFolder. For systems supporting only the 1.0 library, there is only the root folder. The 2.0 library supports a hierarchal structure similar to a file system. The
Tasks property exposes a
TaskCollection instance which can enumerate tasks and provides an indexer which allows access to individual tasks by name. The
TaskCollection class also has methods that allow for the creation/registration and deletion of tasks and subfolders by name.
A task is represented by a
Task instance. The Task class provides information about tasks state and history and exposes the task's
TaskDefinition through the
Definition property.
A
TaskDefinition exposes all of the properties of a task which allow you to define how and what will run when the task is triggered. A task must have at least one action and one trigger defined.
Each task has a list of triggers that determine when the task will be run. These are accessed through the
Triggers property of a task definition which exposes a
TriggerCollection instance.
TriggerCollection provides an indexer which allows access to individual triggers by their position in the list. The
TriggerCollection class also has methods that allow for the addition and removal of triggers.
TriggerCollection implements the IList interface so you can also enumerate all tasks using the foreach construct.
The
Trigger class is an abstract class that forms the foundation of the different types of triggers that can be specified for a task. There are 10 different specializations that provide different ways to specify the time a task will run. Not all specializations work with the 1.0 library. See the help file for details about each of the trigger classes. The
Trigger Documentation has some examples of how to setup each kind of trigger.
The
Action class is an abstract class that is the foundation for four different actions. On 1.0, only the
ExecAction specialization is available. These actions determine what the service will do when a trigger is fired. The
Action Documentation has some examples of how to setup each kind of action.
Below is a brief example of how to use the library from C#.
using System;
using Microsoft.Win32.TaskScheduler;
class Program
{
staticvoid Main(string[] args)
{
// Get the service on the local machineusing (TaskService ts = new TaskService())
{
// Create a new task definition and assign properties
TaskDefinition td = ts.NewTask();
td.RegistrationInfo.Description = "Does something";
// Add a trigger that, starting tomorrow, will fire every other week on Monday// and Saturday and repeat every 10 minutes for the following 11 hours
WeeklyTrigger wt = new WeeklyTrigger();
wt.StartBoundary = DateTime.Today.AddDays(1);
wt.DaysOfWeek = DaysOfTheWeek.Monday | DaysOfTheWeek.Saturday;
wt.WeeksInterval = 2;
wt.Repetition.Duration = TimeSpan.FromHours(11);
wt.Repetition.Interval = TimeSpan.FromMinutes(10);
td.Triggers.Add(wt)
// Create an action that will launch Notepad whenever the trigger fires
td.Actions.Add(new ExecAction("notepad.exe", "c:\\test.log", null));
// Register the task in the root folder
ts.RootFolder.RegisterTaskDefinition("Test", td);
}
}
}Here's the same as above but in VB.NET
Imports Microsoft.Win32.TaskScheduler
Module Module1
Sub Main()
Using ts AsNew TaskService()
' Create a new task definition and assign propertiesDim td As TaskDefinition = ts.NewTask
td.RegistrationInfo.Description = "Does something"' Add a trigger that will, starting tomorrow, fire every other week on Monday' and Saturday and repeat every 10 minutes for the following 11 hoursDim wt AsNew WeeklyTrigger()
wt.StartBoundary = DateTime.Today.AddDays(1)
wt.DaysOfWeek = DaysOfTheWeek.Monday Or DaysOfTheWeek.Saturday
wt.WeeksInterval = 2
wt.Repetition.Duration = TimeSpan.FromHours(11)
wt.Repetition.Interval = TimeSpan.FromMinutes(10)
td.Triggers.Add(wt)
' Add an action (shorthand) that runs Notepad
td.Actions.Add(New ExecAction("notepad.exe", "c:\test.log"))
' Register the task in the root folder
ts.RootFolder.RegisterTaskDefinition("Test", td)
EndUsingEndSubEndModuleIf you're really into shorthand code, here's almost the same functionality as the C# code above, but much shorter:
using System;
using Microsoft.Win32.TaskScheduler;
class Program
{
staticvoid Main(string[] args)
{
new TaskService().AddTask("Test", new DailyTrigger { DaysInterval = 2 }, new ExecAction("notepad.exe", "c:\\test.log", null));
}
}
