windows服务仍在运行但任务没有连续执行

Question

 public Service1()
    {
        InitializeComponent();
    }

    protected override void OnStart(string[] args)
    {

        try
        {
            Print();
        }
        catch (Exception ex)
        {
            File.AppendAllText(@"C:\fold1\Log.txt", ex.ToString());
        }



    }
    public static void Print()
    {
        //Print & Move the files after printing
        DirectoryInfo sourceinfo = new DirectoryInfo(@"C:\fold");
        DirectoryInfo target = new DirectoryInfo(@"C:\fold1");

        foreach (FileInfo fi in sourceinfo.GetFiles())
        {
            if (fi.Length != 0)
            {
                System.Diagnostics.Process process = new System.Diagnostics.Process();
                process.StartInfo.CreateNoWindow = true;
                process.StartInfo.Verb = "print";
                process.StartInfo.FileName = fi.FullName;
                process.StartInfo.UseShellExecute = true;
                process.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
                process.Start();

                if (!process.WaitForExit(10000))
                    process.Kill();
            }

            MoveFile(fi.FullName);
        }
    }

    public static void MoveFile(string Filename)
    {
        string SourcePath = @"C:\fold";
        string targetpath = @"C:\fold1";


        if (!Directory.Exists(targetpath))
        {
            Directory.CreateDirectory(targetpath);
        }

        string[] sourceFiles = Directory.GetFiles(SourcePath);

        foreach (string sourcefile in sourceFiles)
        {
            string mfilename = Path.GetFullPath(sourcefile);
            string mname = Path.GetFileName(sourcefile);

            if (mfilename == Filename)
            {
                string distnition = Path.Combine(targetpath, mname);
                File.Move(mfilename, distnition);
            }
        }

    }
    protected override void OnStop()
    { try
        {
            //Move the files after printing
            DirectoryInfo sourceinfo = new DirectoryInfo(@"C:\fold");
            DirectoryInfo target = new DirectoryInfo(@"C:\fold1");

            foreach (FileInfo fi in sourceinfo.GetFiles())
            {
                // File.AppendAllText(@"C:\fold1\stop.txt", "Stop method");
                MoveFile(fi.FullName);
            }
        } 
        catch (Exception ex)
        {
            File.AppendAllText(@"C:\fold1\Log.txt", ex.ToString());
        }


    }

我创建了一个服务，它在给定目录中静默打印文件，然后将它们移动到另一个目录，当我第一次尝试启动它时它运行良好，但它不会持续运行，我希望它打印和移动任何复制到该目录的文件，那我该怎么办？ 请注意，我还是 c# 的初学者，如果你的解释太复杂，我不太明白，谢谢

Answer 1

问题是，您的OnStart() 方法已经完成了具体的工作并且永远 返回。但是服务管理器被设计成最多等待 60 秒，直到 OnStart() 方法返回，否则进程将被杀死。

因此，与其直接在OnStart() 方法中调用您的代码，不如实例化一个新的任务或线程来完成工作并立即退出OnStart() 方法。在OnStop() 方法中，您必须通知并行运行的代码停止（例如，通过使用CancellationToken）并等待它完成然后退出。

示例

public partial class ServiceExample : ServiceBase
{
    public ServiceExample()
    {
        InitializeComponent();
    }

    private Task Runner;
    private CancellationTokenSource Cts;

    protected override void OnStart(string[] args)
    {
        if (Cts != null) // Could also simply return
            throw new InvalidOperationException("Service is already running!");

        Cts = new CancellationTokenSource();

        Runner = DoSomething(Cts.Token);
    }

    private async Task DoSomething(CancellationToken cancellationToken)
    {
        // Immediately return to caller to avoid "hanging" OnStart()
        await Task.Yield();

        // Regulary check if OnStop() is waiting for us
        while (!cancellationToken.IsCancellationRequested)
        {
            // Call your method that should do something.
            // If it runs longer and can be intercepted,
            // forward the CancellationToken to it.
            await Worker(cancellationToken);
        }
    }

    protected override void OnStop()
    {
        if (Cts == null) // Could also simply return
            throw new InvalidOperationException("Service already being stopped!");

        Cts.Cancel();
        Runner.Wait();
    }

    private async Task Worker(CancellationToken cancellationToken)
    {
        Trace.WriteLine($"{DateTime.UtcNow}: Do some heavy work!");
        await Task.Delay(TimeSpan.FromSeconds(1));

        if (cancellationToken.IsCancellationRequested)
            return;

        await Task.Delay(TimeSpan.FromSeconds(1));
    }
}