Question

我正在寻找出路运行多项任务并报告任务状态而不是顺序。在这里，我粘贴了一个代码，其中多个任务在所有任务完成时运行和报告。

var task1 = Task.Factory.StartNew(() =>
            {
                Thread.Sleep(1000);
                return "dummy value 1";
            });

            var task2 = Task.Factory.StartNew(() =>
            {
                Thread.Sleep(13000);
                return "dummy value 2";
            });

            var task3 = Task.Factory.StartNew(() =>
            {
                Thread.Sleep(2000);
                return "dummy value 3";
            });

            Task.Factory.ContinueWhenAll(new[] { task1, task2, task3 }, tasks =>
            {
                foreach (Task<string> task in tasks)
                {
                    Console.WriteLine(task.Result);
                }
            });
            Console.ReadLine();

task1将花费更少的时间，然后task3将完成，最后一个task2将完成，但ContinueWhenAll始终显示task1已完成，然后task2＆amp; TASK3。我想以这样的方式修改代码，结果是哪个任务快速完成，首先不按顺序显示。在哪里改变代码。请指导。感谢

更新

var taskp = Task.Factory.StartNew(() =>
            {
                var task1 = Task.Factory.StartNew(() =>
                {
                    Thread.Sleep(1000);
                    return "Task1 finished";
                }).ContinueWith((continuation) => { Console.WriteLine(continuation.Result); });

                var task2 = Task.Factory.StartNew(() =>
                {
                    Thread.Sleep(3000);
                    return "Task2 finished";
                }).ContinueWith((continuation) => { Console.WriteLine(continuation.Result); });

                var task3 = Task.Factory.StartNew(() =>
                {
                    Thread.Sleep(2000);
                    return "Task3 finished";
                }).ContinueWith((continuation) => { Console.WriteLine(continuation.Result); });

                return "Main Task finished";
            });


            taskp.ContinueWith(t => Console.WriteLine(t.Result));
            Console.ReadLine();

Answer 1

一个简单的解决方案是单独ContinueWith每项任务。这是一个非常快速和肮脏的例子：

var taskp = Task.Factory.StartNew(() =>
{
    var task1 = Task.Factory.StartNew(() =>
    {
        Thread.Sleep(1000);
        return "dummy value 1";
    }).ContinueWith((continuation) => { Console.WriteLine("task1"); });

    var task2 = Task.Factory.StartNew(() =>
    {
        Thread.Sleep(3000);
        return "dummy value 2";
    }).ContinueWith((continuation) => { Console.WriteLine("task2"); });

    var task3 = Task.Factory.StartNew(() =>
    {
        Thread.Sleep(2000);
        return "dummy value 3";
    }).ContinueWith((continuation) => { Console.WriteLine("task3"); });

    Task.Factory.ContinueWhenAll(new Task[] { task1, task2, task3}, (x) => { Console.WriteLine("Main Task Complete"); });
});

更新代码以适应OP的UPDATE，其中“Main”任务将在所有“内部”任务完成后输出。为了使它taskp返回字符串而不是写它，代码变为

var taskp = Task.Factory.StartNew<string>(() =>
{
    var task1 = ...; //same
    var task2 = ...; //same
    var task3 = ...; //same
    return "Main Task Complete";

}).ContinueWith((x)=> Console.WriteLine(x.Result));

必须使用StartNew<>重载来指定Task拥有Result的返回类型。

关于运行多任务和报告完成后

更新

1 个答案: