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Question

我正在尝试开发一个异步、多线程的 .NET Core 控制台应用程序，但是在实施教程中的代码后，一旦开始实施，代码就被关闭了

Microsoft.Hosting.Lifetime: Information: application is shutting down

开始编写使用异步、多线程执行的方法

private async Task<List<RegistrationData>> ProcessPendingRegistrationsAsync(List<RegistrationData>  registrations)
{
    return registrations;
}

然后我运行这个方法使用“Task.Run”

foreach (var openPendingRegistrationsData in openPendingRegistrationsPerPages)
    processPendingRegistrationsTasks.Add(Task.Run(() => ProcessPendingRegistrationsAsync(openPendingRegistrationsData)
);

最后，我想使用 await Task.WhenAll():

等待所有任务

if (processPendingRegistrationsTasks.Count > 0)
{
    await Task.WhenAll(processPendingRegistrationsTasks);
}

Console.WriteLine("Finish running code");

为了更清楚代码没有在 Console.WriteLine 中打印消息，一旦我实施 Task.WhenAll。

拜托，谁能告诉我问题出在哪里？

编辑

Program.cs

internal class Program
{
    private static void Main(string[] args)
    {
        var log4NetConfiguration = new Log4NetConfiguration();
        log4NetConfiguration.SetLog4NetConfiguration();
        var host = CreateHostDefaultBuilder(args).Build();
        host.RunAsync();
        RunTask(host.Services);
    }

    public static IHostBuilder CreateHostDefaultBuilder(string[] args)
    {
        return Host.CreateDefaultBuilder()
            .ConfigureAppConfiguration(app => { app.AddJsonFile("appsettings.json"); })
            .ConfigureServices((_, services) =>
            {
                services.ConfigureDAL().ConfigureBusiness().ConfigureConnectionHelper().ConfigureTimeOutSetting();
            });
    }

    public static void RunTask(IServiceProvider services)
    {
        var taskHelper = (TaskHelper)services.GetService(typeof(TaskHelper));
        taskHelper?.Execute(true);
    }
}

TaskHelper.cs

public async Task Execute(bool forceMode)
{
    var openPendingRegistrationsPerPages =
            _dRegistration.GetAllRegistrationsByStatusAndSubStatusPerPage(cachedByGuid[1], cachedByGuid[2]);

    foreach (var openPendingRegistrationsData in openPendingRegistrationsPerPages)
        processPendingRegistrationsTasks.Add(Task.Run(() => ProcessPendingRegistrationsAsync(openPendingRegistrationsData));
}

if (processPendingRegistrationsTasks.Count > 0)
{
    await Task.WhenAll(processPendingRegistrationsTasks);
}

Console.WriteLine("Finish running code");


private async Task<List<RegistrationData>> ProcessPendingRegistrationsAsync(List<RegistrationData>  registrations)
{
    // Process
    return registrations;
}

Answer 1

您没有等待 taskHelper.Execute(true) 完成执行。

问题源于您的 RunTask(...) 方法：

public static void RunTask(IServiceProvider services)
{
  var taskHelper = (TaskHelper)services.GetService(typeof(TaskHelper));
  taskHelper?.Execute(true);
}

.Execute returns一个Task:

public async Task Execute(bool forceMode)

除非你await这个调用你不能，因为RunTask不是async方法，你的代码将不会等待Task返回完成方法运行.

在这种情况下，简单的解决方案是使用Task.Wait方法等待任务完成执行。

这应该有效：

public static void RunTask(IServiceProvider services)
{
  var taskHelper = (TaskHelper)services.GetService(typeof(TaskHelper));
  taskHelper?.Execute(true).Wait();
}

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