[. Net Core] simple use of the built-in Mvc Ioc (continued), mvcioc

[. Net Core] simple use of the built-in Mvc Ioc (continued), mvcioc
Simple use of built-in Mvc Ioc (continued)

This article is based on. NET Core 2.0.

The previous chapter [. Net Core] simple use of built-in Mvc Ioc has explained the simple usage of Ioc in daily Mvc. In addition, there are some content to be supplemented.

Next we will answer these questions: What is the combination of Filter and Ioc in AOP? How can I directly retrieve instance objects in Ioc, rather than using Constructors?

 

Directory

• Scenario 1: Use Ioc with Filter
• Scenario 2: directly obtain the object managed by Ioc

 

Scenario 1: Use Ioc with Filter

First, write a filter ExceptionFilter. cs, which inherits the IExceptionFilter and is mainly used to record logs when errors occur. The namespace used is Microsoft. AspNetCore. Mvc. Filters.

using Microsoft.AspNetCore.Mvc.Filters;namespace IocCoreDemo{    public class ExceptionFilter : IExceptionFilter    {        private readonly LogService _logService;        public ExceptionFilter(LogService logService)        {            _logService = logService;        }        public void OnException(ExceptionContext context)        {            _logService.Error(context.Exception.Message);        }    }}

 

LogService. cs:

    public class LogService    {        public void Error(string message)        {            Console.WriteLine(message);        }    }

 

I explicitly asked the Controller Demo4Controller. cs to throw an unimplemented exception in the Index () method for testing:

    public class Demo4Controller : Controller    {        public IActionResult Index()        {            throw new NotImplementedException();        }    }

 

Next, we will modify the code in the ConfigureServices () method of the core Startup. cs. The editor uses AddSingleton () as the example Method for injection:

Public void ConfigureServices (IServiceCollection services) {services. addSingleton (typeof (ExceptionFilter); // inject ExceptionFilter services. addSingleton (typeof (LogService); // inject LogService services. addMvc (x => {// create a ServiceProvider object var provider = services. buildServiceProvider (); var filter = provider. getService <ExceptionFilter> (); // Add filter x. filters. add (filter );});}

 

Public class Demo5Service {public string Test () {return Guid. NewGuid (). ToString ();}}

 

Method 1

We can use this. HttpContext. RequestServices. GetService () in the Controller to obtain the service objects injected into Ioc, such as the controller Demo5Controller. cs:

    public class Demo5Controller : Controller    {        public IActionResult Index()        {            var demoService = (Demo5Service) this.HttpContext.RequestServices.GetService(typeof(Demo5Service));            return Json(demoService.Test());        }    }

 

Do not forget to inject the service class into Startup. cs:

Public class Startup {public static ServiceProvider {get; private set ;}// This method gets called by the runtime. use this method to add services to the container. public void ConfigureServices (IServiceCollection services) {services. addMvc (); services. addSingleton <Demo5Service> (); ServiceProvider = services. buildServiceProvider ();}//...}

 

Public class Demo5Controller: Controller {public IActionResult Index () {var demoService = (Demo5Service) Startup. serviceProvider. getService (typeof (Demo5Service); return Json (demoService. test ());}}

 

 

Original article: http://www.cnblogs.com/liqingwen/p/8585119.html

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[. Net Core] simple use of built-in Mvc Ioc

[. Net Core] simple use of built-in Mvc Ioc (continued)