多线程的并发控制

  当有多个线程同时访问有限制的资源时会出现并发情况，此时可以使用‘信号量’来控制访问资源的线程数量

        static void Main(string[] args)
         {

                int taskCount = 10;//总线程数
                 int seatCount = 4;//资源访问最大线程数量
                 var semaphore = new SemaphoreSlim(seatCount,6);
                 var tasks = new Task[taskCount];
                 for (int i = 0; i < taskCount; i++)
                 {
                     tasks[i] = Task.Run(() => TaskRun(semaphore));
                 }
                 Task.WaitAll(tasks);
                 Console.WriteLine("All Tasks have finished!");
         }
         static void TaskRun(SemaphoreSlim semaphore)
         {
             semaphore.Wait();
             try
             {
                 Console.WriteLine("Task {0} is Running!", Task.CurrentId);
                 Thread.Sleep(1000);
             }
             finally
             {
                 Console.WriteLine("Task {0} have finished!", Task.CurrentId);
                 semaphore.Release();
             }
         }