Task C#后台任务

Task C#后台任务

C# 创建一个没有返回值的任务

using System;
using System.Threading;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        // 创建并启动一个没有返回值的任务
        Task task1 = Task.Run(() =>
        {
            Console.WriteLine("Task 1 is running on a thread pool thread.");
            Thread.Sleep(2000); // Simulate work with Sleep
            Console.WriteLine("Task 1 has completed.");
        });
        // 创建并启动一个有返回值的任务
        Task<int> task2 = Task.Run(() =>
        {
            Console.WriteLine("Task 2 is performing some calculations...");
            Thread.Sleep(1500); // Simulate work with Sleep
            return 42; // Return the result of the calculation
        });
        // Wait for both tasks to complete and handle their results.
        System.Console.WriteLine("Main thread is waiting for Task 1 to complete.");
        await Task.WhenAll(task1, task2);

        // Get the result from task2.
        int result = await task2;
        Console.WriteLine($"The result from Task 2 is: {result}");
    }
}

C# 创建一个可以取消的任务

class Program
{
    static async Task Main(string[] args)
    {
        CancellationTokenSource cts = new CancellationTokenSource();
        try
        {
            Task task3 = Task.Run(
                () =>
                {
                    while (true)
                    {
                        if (cts.Token.IsCancellationRequested)
                        {
                            Console.WriteLine("Cancellation requested, task 3 is stopping.");
                            break;
                        }
                        Console.WriteLine("Task 3 is working...");
                        Thread.Sleep(500);
                    }
                },
                cts.Token
            );

            // Let task3 run for a short time before cancelling it.
            await Task.Delay(2000);
            // 只要cts.Cancel()就会一直运行,👇👇👇👇👇👇👇👇👇👇👇👇
            cts.Cancel(); // Request cancellation after 2 seconds.

            // Wait for task3 to recognize the cancellation request and stop.
            await task3;
        }
        catch (OperationCanceledException ex)
        {
            Console.WriteLine($"Task was cancelled: {ex.Message}");
        }
    }
}