NET Core开发-获取所有注入(DI)服务

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获取ASP.NET Core中所有注入(DI)服务，在ASP.NET Core中加入了Dependency Injection依赖注入。

我们在Controller，或者在ASP.NET Core程序中的其他地方使用注入的服务，如logging 等。

我们要怎样获取ASP.NET Core中所有注入(DI)服务呢，下面我们来一探究竟，也可以来看看ASP.NET Core到底注入了哪些服务。

依赖注入简单介绍：

依赖注入（Dependency injection , DI）是一种实现对象及其合作者或依赖项之间松散耦合的技术。将类用来执行其操作的这些对象以某种方式提供给该类，而不是直接实例化合作者或使用静态引用。

我们新建一个ASP.NET Core 空应用程序。

然后Startup 中定义一个变量 private IServiceCollection _services;

public class Startup
{
private IServiceCollection _services;
// This method gets called by the runtime. Use this method to add services to the container.
// For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940
public void ConfigureServices(IServiceCollection services)
{
_services = services;
} // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
loggerFactory.AddConsole();
var _logger = loggerFactory.CreateLogger("Services");
_logger.LogInformation($"Total Services Registered: {_services.Count}");
foreach (var service in _services)
{
_logger.LogInformation($"Service: {service.ServiceType.FullName}\n Lifetime: {service.Lifetime}\n Instance: {service.ImplementationType?.FullName}");
} if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
} app.Run(async (context) =>
{
await context.Response.WriteAsync("Hello World!");
});
}
}

在 Configure 中使用Logger打印出来。

执行程序，可以看到，默认有14个服务。

然后我们也可以将这些服务在网页中展示出来。

我们在 Configure 中加入如下代码：

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
loggerFactory.AddConsole();
var _logger = loggerFactory.CreateLogger("Services");
_logger.LogInformation($"Total Services Registered: {_services.Count}");
foreach (var service in _services)
{
_logger.LogInformation($"Service: {service.ServiceType.FullName}\n Lifetime: {service.Lifetime}\n Instance: {service.ImplementationType?.FullName}");
} if (env.IsDevelopment())
{
app.Map("/allservices", builder => builder.Run(async context =>
{
context.Response.ContentType = "text/html; charset=utf-8";
await context.Response.WriteAsync($"<h1>所有服务{_services.Count}个</h1><table><thead><tr><th>类型</th><th>生命周期</th><th>Instance</th></tr></thead><tbody>");
foreach (var svc in _services)
{
await context.Response.WriteAsync("<tr>");
await context.Response.WriteAsync($"<td>{svc.ServiceType.FullName}</td>");
await context.Response.WriteAsync($"<td>{svc.Lifetime}</td>");
await context.Response.WriteAsync($"<td>{svc.ImplementationType?.FullName}</td>");
await context.Response.WriteAsync("</tr>");
}
await context.Response.WriteAsync("</tbody></table>");
}));
app.UseDeveloperExceptionPage();
} app.Run(async (context) =>
{
await context.Response.WriteAsync("Hello World!");
});
}