一、线程不安全例子

计数

const int total = 100_000;int count = 0;var thread1 = new Thread(Increment);
var thread2 = new Thread(Increment);thread1.Start();
thread2.Start();thread1.Join();
thread2.Join();Console.WriteLine($"Count: {count}");void Increment()
{for (int i = 0; i < total; i++)count++;
}

操作队列

var queue = new Queue<int>();var producer = new Thread(Producer);
var consumer1 = new Thread(Consumer);
var consumer2 = new Thread(Consumer);producer.Start();
consumer1.Start();
consumer2.Start();producer.Join();
Thread.Sleep(100); // Wait for consumers to finishconsumer1.Interrupt();
consumer2.Interrupt();
consumer1.Join();
consumer2.Join();void Producer()
{for (int i = 0; i < 20; i++){Thread.Sleep(20);queue.Enqueue(i);}
}void Consumer()
{try{while (true){if (queue.TryDequeue(out var res))Console.WriteLine(res);Thread.Sleep(1);}}catch (ThreadInterruptedException){Console.WriteLine("Thread interrupted.");}
}

二、Parallel与PLINQ

var inputs = Enumerable.Range(1,20).ToArray();int HeavyJob(int input)
{Thread.Sleep(300);return input;
}// Sequential
var forOutputs = new int[inputs.Length];
for (int i = 0; i < inputs.Length; i++)
{forOutputs[i] = HeavyJob(inputs[i]);
}// Parallel
var parallelOutputs = new int[inputs.Length];
Parallel.For(0, inputs.Length, i =>
{parallelOutputs[i] = HeavyJob(inputs[i]);
});// PLINQ
var plinqOutputs = inputs.AsParallel().Select(HeavyJob).ToArray();

三、PLINQ 与信号量

using System.Diagnostics;var inputs = Enumerable.Range(1,20).ToArray();
var semaphore = new Semaphore(3, 3);int HeavyJob(int input)
{semaphore.WaitOne();Thread.Sleep(300);semaphore.Release();return input;
}var sw = Stopwatch.StartNew();
var plinqOutputs = inputs.AsParallel().Select(HeavyJob).ToArray();
sw.Stop();
Console.WriteLine($"Elapsed time: {sw.ElapsedMilliseconds}ms");

四、线程终止

//线程终止
var thread = new Thread(() =>
{try{for (int i = 0; i < 10; i++){Thread.Sleep(1000);Console.WriteLine("Sub thread: " + i);}}catch (ThreadInterruptedException){Console.WriteLine("Thread interrupted");}
});thread.Start();
Thread.Sleep(3500);
thread.Interrupt();
thread.Join();
Console.WriteLine("Done");