在C#console应用程序中更改线程上下文

我使用了一个计时器线程和一个用户输入线程来模拟生成作业的2个线程.您可以实现TCP事件,以便在作业队列中排队作业.您应该将任何相关对象作为参数存储在作业中,以便以后处理.您还必须定义要由作业调用的函数,该函数将在主线程中运行.

这里使用的主要线程只是为了使作业出列并处理它们,但是如果你稍微改进一下这个代码就可以使用任何其他线程来实现这个目的.

您甚至可以实现多线程处理,其中更多处理线程从同一作业队列中出列.请注意,这会带来您可能需要处理的新并发问题.这是在您的应用程序中获得更多处理能力的缺点.一些场景适用于多线程处理(例如视频/图像处理)而另一些场景则不适用.

下面的代码是一个完整的工作示例,用Visual Studio 2017,DotNET 4.6.1,控制台应用程序项目编写.只需复制,粘贴并点击F5即可.

using System;
using System.Collections.Concurrent;
using System.Diagnostics;
using System.Threading;

// Compiled and tested in: Visual Studio 2017,DotNET 4.6.1

namespace MyNamespace
{
    public class Program
    {
        public static void Main(string[] args)
        {
            MyApplication app = new MyApplication();
            app.Run();
        }
    }

    public class MyApplication
    {
        private BlockingCollection<Job> JobQueue = new BlockingCollection<Job>();
        private CancellationTokenSource JobCancellationTokenSource = new CancellationTokenSource();
        private CancellationToken JobCancellationToken;
        private Timer Timer;
        private Thread UserInputThread;



        public void Run()
        {
            // Give a name to the main thread:
            Thread.CurrentThread.Name = "Main";

            // Fires a Timer thread:
            Timer = new Timer(new TimerCallback(TimerCallback),null,1000,2000);

            // Fires a thread to read user inputs:
            UserInputThread = new Thread(new ThreadStart(ReadUserInputs))
            {
                Name = "UserInputs",IsBackground = true
            };
            UserInputThread.Start();

            // Prepares a token to cancel the job queue:
            JobCancellationToken = JobCancellationTokenSource.Token;

            // Start processing jobs:
            ProcessJobs();

            // Clean up:
            JobQueue.Dispose();
            Timer.Dispose();
            UserInputThread.Abort();

            Console.WriteLine("Done.");
        }



        private void ProcessJobs()
        {
            try
            {
                // Checks if the blocking collection is still up for dequeueing:
                while (!JobQueue.IsCompleted)
                {
                    // The following line blocks the thread until a job is available or throws an exception in case the token is cancelled:
                    JobQueue.Take(JobCancellationToken).Run();
                }
            }
            catch { }
        }



        private void ReadUserInputs()
        {
            // User input thread is running here.
            ConsoleKey key = ConsoleKey.Enter;

            // Reads user inputs and queue them for processing until the escape key is pressed:
            while ((key = Console.ReadKey(true).Key) != ConsoleKey.Escape)
            {
                Job userInputJob = new Job("UserInput",this,new Action<ConsoleKey>(ProcessUserInputs),key);
                JobQueue.Add(userInputJob);
            }
            // Stops processing the JobQueue:
            JobCancellationTokenSource.Cancel();
        }

        private void ProcessUserInputs(ConsoleKey key)
        {
            // Main thread is running here.
            Console.WriteLine($"You just typed '{key}'. (Thread: {Thread.CurrentThread.Name})");
        }



        private void TimerCallback(object param)
        {
            // Timer thread is running here.
            Job job = new Job("TimerJob",new Action<string>(ProcessTimer),"A job from timer callback was processed.");
            JobQueue.TryAdd(job); // Just enqueues the job for later processing
        }

        private void ProcessTimer(string message)
        {
            // Main thread is running here.
            Console.WriteLine($"{message} (Thread: {Thread.CurrentThread.Name})");
        }
    }



    /// <summary>
    /// The Job class wraps an object's method call,with or without arguments. This method is called later,during the Job execution.
    /// </summary>
    public class Job
    {
        public string Name { get; }
        private object TargetObject;
        private Delegate TargetMethod;
        private object[] Arguments;

        public Job(string name,object obj,Delegate method,params object[] args)
        {
            Name = name;
            TargetObject = obj;
            TargetMethod = method;
            Arguments = args;
        }

        public void Run()
        {
            try
            {
                TargetMethod.Method.Invoke(TargetObject,Arguments);
            }
            catch(Exception ex)
            {
                Debug.WriteLine($"Unexpected error running job '{Name}': {ex}");
            }
        }

    }
}