Question

我有一个简单的控制台应用程序，当它执行时：

1 - 在新线程中启动一个方法，一段时间后，在控制台中显示＆＃34;生成值已完成＆＃34;
2 - 立即显示＆＃34;主线程已完成＆＃34;

这是我的代码：

    static void Main(string[] args)
    {
        Start();
        Console.WriteLine("main thread is finished");
        Console.ReadLine();
    }

    private static int GenerateValue(int value)
    {
        int milliseconds = 10000;
        Thread.Sleep(milliseconds);
        return value*2;
    }

    private static void Start()
    {
        ThreadStart starter = () => GenerateValue(5);
        starter += () =>
        {
            Console.WriteLine("generate value is finished");
        };
        Thread thread = new Thread(starter) { IsBackground = true };
        thread.Start();
    }

我想要带来的改进是显示＆＃34;生成值已完成＆＃34;，生成的值，例如此处＆＃34; 10＆＃34;。

但是我看不到如何在委托回调中访问＆＃34; GenerateValue（5）＆＃34;返回的值。：

    starter += () =>
    {
       // Is it possible here to access to the value (that will be 10) 
       // returned by GenerateValue(5)
        Console.WriteLine("generate value is finished");
    };

Answer 1

你可以用一个闭包来实现这个目的：

private static void Start()
{
    int returnValue = 0;
    ThreadStart starter = () =>
    {
        returnValue = GenerateValue(5);
    };
    starter += () =>
    {
        Console.WriteLine("generate value is finished. Returned value is {0}", returnValue);
    };
    Thread thread = new Thread(starter) { IsBackground = true };
    thread.Start();
}

在回调中获取threadstarter委托的返回值

1 个答案: