C#中限制并发任务数量的高效方法与技巧分享

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        int maxConcurrentTasks = 3;
        SemaphoreSlim semaphore = new SemaphoreSlim(maxConcurrentTasks);
        List<Task> tasks = new List<Task>();

        for (int i = 0; i < 100; i++)
        {
            await semaphore.WaitAsync();
            var task = Task.Run(async () =>
            {
                try
                {
                    // 模拟长时间运行的任务
                    Console.WriteLine($"Task {Task.CurrentId} started.");
                    await Task.Delay(TimeSpan.FromSeconds(2));
                    Console.WriteLine($"Task {Task.CurrentId} completed.");
                }
                finally
                {
                    semaphore.Release();
                }
            });
            tasks.Add(task);
        }

        await Task.WhenAll(tasks);
        Console.WriteLine("All tasks completed.");
    }
}

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

class Program
{
    static async Task Main(string[] args)
    {
        var options = new ExecutionDataflowBlockOptions
        {
            MaxDegreeOfParallelism = 3 // 最大并发任务数量
        };

        var block = new ActionBlock<int>(async n =>
        {
            Console.WriteLine($"Processing {n}...");
            await Task.Delay(TimeSpan.FromSeconds(1)); // 模拟异步操作
            Console.WriteLine($"Processed {n}.");
        }, options);

        for (int i = 0; i < 100; i++)
        {
            block.Post(i);
        }

        block.Complete();
        await block.Completion;
        Console.WriteLine("All tasks completed.");
    }
}