创建 .NET Core Console App

在 Visual Studio 2019 中创建一个 Console App

在解决方案中添加其他层， 创建类似于下图的解决方案项目结构：

添加 NuGet 包

在 控制台项目中添加以下三个NuGet包：

  1. Microsoft.Extensions.DependencyInjection;
  2. Microsoft.Extensions.Hosting;
  3. Microsoft.Extensions.Logging;

添加 DI 容器

打包 控制台项目中的 program.cs 文件，将其代码中的 main() 修改为以下内容:

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class Program
{
    static async System.Threading.Tasks.Task Main(string[] args)
    {

        var builder = new HostBuilder()
            .ConfigureServices((hostContext, services)=> {
                services.AddLogging(configure => configure.AddConsole());
                services.AddTransient<MyApplication>();
                services.AddSingleton<ISampleClient, SampleClient>();
                services.AddTransient<HttpClient>();
               
            });
        var host = builder.Build();            
        using (var serviceScope = host.Services.CreateScope()) {
            var services = serviceScope.ServiceProvider;                              
            try
            {
                var myService = services.GetRequiredService<MyApplication>();
                await myService.Run();
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error Occured:  {0}", ex);
            }
        }
    }
}

控制台项目中的 MyApplication.cs 文件类似于以下内容：

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public class MyApplication
    {
        private readonly ILogger _logger;
        private readonly IBusinessLayer _business;
        public MyApplication(ILogger<MyApplication> logger, IBusinessLayer business)
        {
            _logger = logger;
            _business = business;
        }

        internal async Task Run()
        {
            _logger.LogInformation("Application {applicationEvent} at {dateTime}", "Started", DateTime.UtcNow);

            _business.PerformBusiness();

            _logger.LogInformation("Application {applicationEvent} at {dateTime}", "Ended", DateTime.UtcNow);

            Console.WriteLine("PRESS <ENTER> TO EXIT");
            Console.ReadKey();
        }
    }

===END===