Ответ 1
Исходное сообщение: я написал это примерное консольное приложение (используя С# 4.0 [как указано параметрами по умолчанию]). Он чрезвычайно универсален и использует делегата Action, чтобы разрешить передачу которые вы хотите выполнить с помощью класса Таймер (в System.Threading). Перегруженный метод Do статичного Atкласс выполняет всю работу по вычислению интервала задержки. Вы может необязательно повторять повторную операцию, указав интервал (в миллисекунды). Вы можете, конечно, изменить метод, чтобы принять TimeSpan для интервала повторения.
Пример приложения консоли, представленный три года назад, оказался довольно популярным для людей, которые ищут что-то подобное. Многие из заданных вопросов касались управления расписанием работы. Я сделал попытку написать новый класс, который можно реализовать довольно просто. Он был представлен только в качестве примера использования. Для тех, кто считает, что мой стиль уступает или пронизан ненужным кодом, это прекрасно. Это зависит от вас, чтобы настроить его для вашего стиля программирования, практики внедрения и т.д.
Следующие изменения в классе делают его более удобным:
- Создание заданий с помощью метода Do() работает аналогично старому классу. Был добавлен дополнительный необязательный ключ параметра (объект типа), позволяющий указать имя задания. Это имя позволит вам изменить ранее запланированные задания (продолжать чтение).
- Объекты с мгновенным таймером хранятся внутри класса, что позволяет вам иметь несколько запланированных задач, на которые можно ссылаться по имени индивидуально.
- Добавлены новые обработчики для управления заданиями (с использованием ключа). Они предоставляются методами SuspendJob(), GetJobFor(), EndJob() и ResumeJob.
- Статический конструктор подписывается на событие AppDomain.CurrentDomain.DomainUnload для "deconstructor" для размещения любых запущенных заданий при выгрузке приложения (приложения).
- Была добавлена проверка параметров, чтобы убедиться, что параметры ожидаются.
- Ограниченная блокировка позволяет добавлять задания из любого потока.
Что не изменилось?
- В примере не обрабатывается результат делегата Действие. Если вам нужно что-то лучше, реализуйте его.:)
Прокрутите вниз, чтобы найти новую реализацию класса. Наслаждайтесь!
** Старый класс консоли выглядит следующим образом: **
using System;
using System.Threading;
namespace ConsoleApplication1
{
/// <summary>
/// Class that manages the execution of tasks sometime in the future.
/// </summary>
public static class At
{
#region Members
/// <summary>
/// Specifies the method that will be fired to execute the delayed anonymous method.
/// </summary>
private readonly static TimerCallback timer = new TimerCallback(At.ExecuteDelayedAction);
#endregion
#region Methods
/// <summary>
/// Method that executes an anonymous method after a delay period.
/// </summary>
/// <param name="action">The anonymous method that needs to be executed.</param>
/// <param name="delay">The period of delay to wait before executing.</param>
/// <param name="interval">The period (in milliseconds) to delay before executing the anonymous method again (Timeout.Infinite to disable).</param>
public static void Do(Action action, TimeSpan delay, int interval = Timeout.Infinite)
{
// create a new thread timer to execute the method after the delay
new Timer(timer, action, Convert.ToInt32(delay.TotalMilliseconds), interval);
return;
}
/// <summary>
/// Method that executes an anonymous method after a delay period.
/// </summary>
/// <param name="action">The anonymous method that needs to be executed.</param>
/// <param name="delay">The period of delay (in milliseconds) to wait before executing.</param>
/// <param name="interval">The period (in milliseconds) to delay before executing the anonymous method again (Timeout.Infinite to disable).</param>
public static void Do(Action action, int delay, int interval = Timeout.Infinite)
{
Do(action, TimeSpan.FromMilliseconds(delay), interval);
return;
}
/// <summary>
/// Method that executes an anonymous method after a delay period.
/// </summary>
/// <param name="action">The anonymous method that needs to be executed.</param>
/// <param name="dueTime">The due time when this method needs to be executed.</param>
/// <param name="interval">The period (in milliseconds) to delay before executing the anonymous method again (Timeout.Infinite to disable).</param>
public static void Do(Action action, DateTime dueTime, int interval = Timeout.Infinite)
{
if (dueTime < DateTime.Now)
{
throw new ArgumentOutOfRangeException("dueTime", "The specified due time has already elapsed.");
}
Do(action, dueTime - DateTime.Now, interval);
return;
}
/// <summary>
/// Method that executes a delayed action after a specific interval.
/// </summary>
/// <param name="o">The Action delegate that is to be executed.</param>
/// <remarks>This method is invoked on its own thread.</remarks>
private static void ExecuteDelayedAction(object o)
{
// invoke the anonymous method
(o as Action).Invoke();
return;
}
#endregion
}
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Time: {0} - started", DateTime.Now);
// demonstrate that order is irrelevant
At.Do(() => Console.WriteLine("Time: {0} - Hello World! (after 5s)", DateTime.Now), DateTime.Now.AddSeconds(5));
At.Do(() => Console.WriteLine("Time: {0} - Hello World! (after 3s)", DateTime.Now), DateTime.Now.AddSeconds(3));
At.Do(() => Console.WriteLine("Time: {0} - Hello World! (after 1s)", DateTime.Now), DateTime.Now.AddSeconds(1));
At.Do
(
() =>
{
// demonstrate flexibility of anonymous methods
for (int i = 0; i < 10; i++)
{
Console.WriteLine("Time: {0} - Hello World! - i == {1} (after 4s)", DateTime.Now, i);
}
},
TimeSpan.FromSeconds(4)
);
// block main thread to show execution of background threads
Thread.Sleep(100000);
return;
}
}
}
** Новый класс предоставляется следующим образом: **
using System;
using System.Linq;
using System.Threading;
using System.Collections.Generic;
namespace Utility
{
/// <summary>
/// Class that is designed to execution Action-based anonymous delegates after a specified
/// interval. This class also supports repetitive tasks on an interval.
/// </summary>
public static class At
{
#region Embedded Classes
/// <summary>
/// Embedded class definition for common At job periods.
/// </summary>
public static class Periods
{
#region Members
/// <summary>
/// Specifies an object that indicates to not restart.
/// </summary>
public static readonly TimeSpan DoNotStart = TimeSpan.FromMilliseconds(-1.0);
/// <summary>
/// Specifies an object that indicates to start immediately.
/// </summary>
public static readonly TimeSpan Immediately = TimeSpan.FromMilliseconds(0.0);
/// <summary>
/// Specifies an interval of one second.
/// </summary>
public static readonly TimeSpan SecondsOne = TimeSpan.FromSeconds(1.0);
/// <summary>
/// Specifies an interval of five seconds.
/// </summary>
public static readonly TimeSpan SecondsFive = TimeSpan.FromSeconds(5.0);
/// <summary>
/// Specifies an interval of fifteen seconds.
/// </summary>
public static readonly TimeSpan SecondsFifteen = TimeSpan.FromSeconds(15.0);
/// <summary>
/// Specifies an interval of thirty seconds.
/// </summary>
public static readonly TimeSpan SecondsThirty = TimeSpan.FromSeconds(30.0);
/// <summary>
/// Specifies an interval of 100ms.
/// </summary>
public static readonly TimeSpan MicroDelay = TimeSpan.FromMilliseconds(100);
#endregion
}
#endregion
#region Members
/// <summary>
/// Specifies an object that can be used for synchronization.
/// </summary>
private readonly static object syncRoot;
/// <summary>
/// Specifies a collection of Timer object that were created for interval-based execution.
/// </summary>
/// <remarks>
/// We must keep these in a collection to prevent the GC from disposing of the timers.
/// </remarks>
private readonly static Dictionary<object, Timer> ActiveTimers;
/// <summary>
/// Specifies a collection of timestamps of when timers are created.
/// </summary>
private readonly static Dictionary<object, DateTime> TimerCreation;
/// <summary>
/// Specifies an object that will produce pseudo-random numbers.
/// </summary>
private readonly static Random RNG;
#endregion
#region Static Constructor
static At()
{
syncRoot = new object();
ActiveTimers = new Dictionary<object, Timer>();
TimerCreation = new Dictionary<object, DateTime>();
RNG = new Random();
// "deconstructor"
AppDomain.CurrentDomain.DomainUnload += new EventHandler(CurrentDomain_DomainUnload);
return;
}
/// <summary>
/// Method used to cleanup resources used by this object.
/// </summary>
static void CurrentDomain_DomainUnload(object sender, EventArgs e)
{
// dispose of all the timers directly
At.ActiveTimers.Values.ToList().ForEach(a => a.Dispose());
return;
}
#endregion
#region Methods
#region At Job Staging
/// <summary>
/// Method that executes an anonymous method after a delay period.
/// </summary>
/// <param name="action">The anonymous method that needs to be executed.</param>
/// <param name="delay">The period of delay to wait before executing.</param>
/// <param name="interval">The period (in milliseconds) to delay before executing the anonymous method again (Timeout.Infinite to disable).</param>
public static Timer Do(Action action, TimeSpan delay, TimeSpan? onInterval = null, object key = null)
{
Timer timer;
if (key == null)
{
// auto-generate a key
key = string.Concat("Auto(", At.RNG.NextNonNegativeLong(), ")");
}
lock (At.ActiveTimers)
{
// action - contains the method that we wish to invoke
At.ActiveTimers.Add(key, timer = new Timer(ActionInvoker, action, delay, onInterval ?? At.Periods.DoNotStart));
At.TimerCreation.Add(key, DateTime.Now);
}
//Log.Message
//(
// LogMessageType.Debug,
// "[DEBUG] {0}: registered At job (key = {1}, initial delay = {2}, interval = {3})",
// action,
// key,
// delay,
// (onInterval == null) ? "never" : onInterval.Value.ToString()
//);
return timer;
}
/// <summary>
/// Method that executes an anonymous method after a delay period.
/// </summary>
/// <param name="action">The anonymous method that needs to be executed.</param>
/// <param name="delay">The period of delay (in milliseconds) to wait before executing.</param>
/// <param name="interval">The period (in milliseconds) to delay before executing the anonymous method again (Timeout.Infinite to disable).</param>
public static Timer Do(Action action, int delay, int interval = Timeout.Infinite, object key = null)
{
return Do(action, TimeSpan.FromMilliseconds(delay), TimeSpan.FromMilliseconds(interval), key);
}
/// <summary>
/// Method that executes an anonymous method after a delay period.
/// </summary>
/// <param name="action">The anonymous method that needs to be executed.</param>
/// <param name="dueTime">The due time when this method needs to be executed.</param>
/// <param name="interval">The period (in milliseconds) to delay before executing the anonymous method again (Timeout.Infinite to disable).</param>
public static Timer Do(Action action, DateTime dueTime, int interval = Timeout.Infinite, object key = null)
{
if (dueTime < DateTime.Now)
{
throw new ArgumentOutOfRangeException("dueTime", "The specified due time has already elapsed.");
}
return Do(action, dueTime - DateTime.Now, TimeSpan.FromMilliseconds(interval), key);
}
#endregion
#region At Job Retrieval
/// <summary>
/// Method that attempts to retrieve a job (Timer object) for a given key.
/// </summary>
/// <param name="key">The key that we are getting a job for.</param>
public static Timer GetJobFor(object key)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
lock (At.ActiveTimers)
{
if (At.ActiveTimers.ContainsKey(key) == false)
{
/*
Log.Message
(
LogMessageType.Error,
"[ERROR] At({0}): unable to find a job with specified key",
key
);
*/
return null;
}
return At.ActiveTimers[key];
}
}
/// <summary>
/// Method that ends a job and removes all resources associated with it.
/// </summary>
/// <param name="key">The key that we are getting a job for.</param>
public static void EndJob(object key)
{
Timer timer;
if ((timer = GetJobFor(key)) == null)
{
// no timer - cannot suspend
return;
}
// dispose of the timer object
timer.Dispose();
lock (At.ActiveTimers)
{
// remove the existence from the dictionary
At.ActiveTimers.Remove(key);
/*
Log.Message
(
LogMessageType.Info,
"[INFO] At({0}): job has been disposed (created {1}, duration {2})",
key,
TimerCreation[key].ToISODateTime(),
(DateTime.Now - TimerCreation[key]).ToText()
);
*/
At.TimerCreation.Remove(key);
}
return;
}
/// <summary>
/// Method that attempts to suspend an active job (using the provided key).
/// </summary>
/// <param name="key">The key that we are getting a job for.</param>
public static void SuspendJob(object key)
{
Timer timer;
if ((timer = GetJobFor(key)) == null)
{
// no timer - cannot suspend
return;
}
// set the timer to not restart
timer.Change(TimeSpan.FromMilliseconds(-1), TimeSpan.FromMilliseconds(-1));
/*
Log.Message
(
LogMessageType.Info,
"[INFO] At({0}): job has been suspended",
key
);
*/
return;
}
/// <summary>
/// Method that attempts to resume an active job (using the provided key).
/// </summary>
/// <param name="key">The key that we are getting a job for.</param>
/// <param name="delay">The amount of delay before restarting the job (specify <b>0</b> to restart immediately).</param>
/// <param name="interval">The delay between intervals (specify <b>-1ms</b> to prevent intervals).</param>
public static void ResumeJob(object key, TimeSpan delay, TimeSpan interval)
{
Timer timer;
if ((timer = GetJobFor(key)) == null)
{
// no timer - cannot suspend
return;
}
// set the timer to not restart
timer.Change(delay, interval);
/*
Log.Message
(
LogMessageType.Info,
"[INFO] At({0}): job has been resumed (delay = {1}, interval = {2})",
key,
delay,
interval
);
*/
return;
}
#endregion
/// <summary>
/// Method that invokes an action delegate on a timer.
/// </summary>
/// <param name="o">A reference to the action that is to be taken.</param>
private static void ActionInvoker(object o)
{
// invoke the delegate
(o as Action).Invoke();
return;
}
#endregion
}
}