1.什么是线程？
进程作为操作系统执行程序的基本单位，拥有应用程序的资源，进程包含线程，进程的资源被线程共享，线程不拥有资源。
2.前台线程和后台线程的区别？
程序关闭时，后台线程直接关闭，但前台线程会执行完后关闭。
通过Thread类新建线程默认为前台线程。其他方式创建的都是后台线程。
多线程的几种方式
一. 异步多线程
static void Main(string[] args)
{
Console.WriteLine("----------主程序开始，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
for(int i = 0; i< 5;i++)
{
Action<string> action = t =>
{
for(int k = 0; k< 1000000000;k++)
{ }
Console.WriteLine("当前参数是{0},当前线程是{1}",t,Thread.CurrentThread.ManagedThreadId);
};
action.BeginInvoke("参数是" + i, null, null);
}
Console.WriteLine("----------主程序结束，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
Console.Read();
}
}二. Threads线程
static void Main(string[] args)
{
Console.WriteLine("----------主程序开始，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
for(int i = 0; i< 5;i++)
{
ParameterizedThreadStart threadStart = t =>
{
for (int k = 0; k < 1000000000; k++)
{ }
Console.WriteLine("当前参数是{0},当前线程是{1}", t, Thread.CurrentThread.ManagedThreadId);
};
Thread thread = new Thread(threadStart);
thread.Start(i);
}
Console.WriteLine("----------主程序结束，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
Console.Read();
}三. ThreadPool线程池
static void Main(string[] args)
{
Console.WriteLine("----------主程序开始，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
for(int i = 0; i< 5;i++)
{
WaitCallback waitCallback = t =>
{
for (int k = 0; k < 1000000000; k++)
{ }
Console.WriteLine("当前参数是{0},当前线程是{1}", t, Thread.CurrentThread.ManagedThreadId);
};
ThreadPool.QueueUserWorkItem(waitCallback, i);
}
Console.WriteLine("----------主程序结束，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
Console.Read();
}四. Task
static void Main(string[] args)
{
Console.WriteLine("----------主程序开始，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
TaskFactory taskFactory = new TaskFactory();
for (int i = 0; i< 5;i++)
{
Action<object> action = t =>
{
for (int k = 0; k < 1000000000; k++)
{ }
Console.WriteLine("当前参数是{0},当前线程是{1}", t, Thread.CurrentThread.ManagedThreadId);
};
taskFactory.StartNew(action,i);
}
Console.WriteLine("----------主程序结束，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
Console.Read();
}五. Parallel
static void Main(string[] args)
{
Console.WriteLine("----------主程序开始，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
Action action1 = () =>
{
for (int k = 0; k < 1000000000; k++)
{ }
Console.WriteLine("当前参数是1,当前线程是{0}", Thread.CurrentThread.ManagedThreadId);
};
Action action2 = () =>
{
for (int k = 0; k < 1000000000; k++)
{ }
Console.WriteLine("当前参数是2,当前线程是{0}", Thread.CurrentThread.ManagedThreadId);
};
Action action3 = () =>
{
for (int k = 0; k < 1000000000; k++)
{ }
Console.WriteLine("当前参数是3,当前线程是{0}", Thread.CurrentThread.ManagedThreadId);
};
Parallel.Invoke(action1, action2, action3);
Console.WriteLine("----------主程序结束，线程ID是{0}-----------------", Thread.CurrentThread.ManagedThreadId);
Console.Read();
}
