Redis数据过期、淘汰策略

在C#中，主要有三种类型的Timer：

System.Windows.Forms.Timer
System.Timers.Timer
System.Threading.Timer
以下是每种Timer的简要说明和示例：

1. System.Windows.Forms.Timer

用于Windows Forms应用程序，适合在UI线程中使用。

using System;
using System.Windows.Forms;

public class WinFormsTimerExample : Form
{
    private Timer timer;

    public WinFormsTimerExample()
    {
        timer = new Timer();
        timer.Interval = 1000; // 1秒
        timer.Tick += new EventHandler(OnTimerEvent);
        timer.Start();
    }

    private void OnTimerEvent(Object sender, EventArgs e)
    {
        Console.WriteLine("WinForms Timer ticked at: " + DateTime.Now);
    }

    [STAThread]
    public static void Main()
    {
        Application.Run(new WinFormsTimerExample());
    }

}

2. System.Timers.Timer

适用于需要更精确的计时和跨线程操作的场景。

using System;
using System.Timers;

public class TimersTimerExample
{
    private static Timer timer;

    public static void Main()
    {
        timer = new Timer(1000); // 1秒
        timer.Elapsed += OnTimedEvent;
        timer.AutoReset = true;
        timer.Enabled = true;

        Console.WriteLine("Press Enter to exit the program...");
        Console.ReadLine();
    }

    private static void OnTimedEvent(Object source, ElapsedEventArgs e)
    {
        Console.WriteLine("Timers Timer ticked at: " + e.SignalTime);
    }
}

3. System.Threading.Timer

用于多线程环境，可以在任何线程上执行回调。

using System;
using System.Threading;

public class ThreadingTimerExample
{
    private static Timer timer;

    public static void Main()
    {
        TimerCallback callback = new TimerCallback(OnTimerEvent);
        timer = new Timer(callback, null, 0, 1000); // 1秒

        Console.WriteLine("Press Enter to exit the program...");
        Console.ReadLine();
    }

    private static void OnTimerEvent(Object state)
    {
        Console.WriteLine("Threading Timer ticked at: " + DateTime.Now);
    }
}

通过这些示例，可以快速掌握每种Timer的使用场景和方法。