c#死锁的案例分析

在C#中，死锁是一种常见的多线程问题，当两个或多个线程互相等待对方释放资源时，就会发生死锁。下面是一个简单的C#死锁案例分析：

using System; using System.Threading;  class Program {     private static object lock1 = new object();     private static object lock2 = new object();      static void Main(string[] args)     {         Thread t1 = new Thread(Thread1);         Thread t2 = new Thread(Thread2);          t1.Start();         t2.Start();          t1.Join();         t2.Join();          Console.WriteLine("Finished");     }      static void Thread1()     {         lock (lock1)         {             Console.WriteLine("Thread1: Locked lock1");             Thread.Sleep(1000);              lock (lock2)             {                 Console.WriteLine("Thread1: Locked lock2");             }         }     }      static void Thread2()     {         lock (lock2)         {             Console.WriteLine("Thread2: Locked lock2");             Thread.Sleep(1000);              lock (lock1)             {                 Console.WriteLine("Thread2: Locked lock1");             }         }     } } 

在这个例子中，我们有两个线程t1和t2，以及两个锁对象lock1和lock2。Thread1函数首先锁定lock1，然后尝试锁定lock2。与此同时，Thread2函数首先锁定lock2，然后尝试锁定lock1。由于两个线程都在等待对方释放锁，因此发生了死锁。

为了解决这个问题，我们可以确保所有线程按照相同的顺序获取锁。修改后的代码如下：

using System; using System.Threading;  class Program {     private static object lock1 = new object();     private static object lock2 = new object();      static void Main(string[] args)     {         Thread t1 = new Thread(Thread1);         Thread t2 = new Thread(Thread2);          t1.Start();         t2.Start();          t1.Join();         t2.Join();          Console.WriteLine("Finished");     }      static void Thread1()     {         lock (lock1)         {             Console.WriteLine("Thread1: Locked lock1");             Thread.Sleep(1000);              lock (lock2)             {                 Console.WriteLine("Thread1: Locked lock2");             }         }     }      static void Thread2()     {         lock (lock1) // 修改这里，确保按照相同的顺序获取锁         {             Console.WriteLine("Thread2: Locked lock1");             Thread.Sleep(1000);              lock (lock2)             {                 Console.WriteLine("Thread2: Locked lock2");             }         }     } } 

现在，Thread2函数首先尝试获取lock1，然后再获取lock2，这样就避免了死锁的发生。