Autofac in webapi2

安装包：Autofac.webapi2 

注意：

 install-package autofac.webapi2 (注意：您的项目中如果使用的是webapi2，此处必须为webapi2而不是webapi,否则在运行时将出现“重写成员“Autofac.Integration.WebApi.AutofacWebApiDependencyResolver.BeginScope()”时违反了继承安全性规则。重写方法的安全可访问性必须与所重写方法的安全可访问性匹配。”错误。)

在global 中 的Application_Start()添加

var builder = new ContainerBuilder();
//builder.RegisterControllers(Assembly.GetExecutingAssembly()); //Register MVC Controllers
builder.RegisterApiControllers(Assembly.GetExecutingAssembly()); //Register WebApi Controllers
//Register any other components required by your code....
builder.RegisterType<UserTest2>().As<IUserTest>();
var container = builder.Build();

// DependencyResolver.SetResolver(new AutofacDependencyResolver(container)); //Set the MVC DependencyResolver
GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver((IContainer)container); //Set the WebApi DependencyResolver

UserTest接口：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace webapiTest
{
public interface IUserTest
{
int GetI(int i);
}

public class UserTest : IUserTest
{
public int GetI(int i)
{
return i;
}
}

public class UserTest2 : IUserTest
{
public int GetI(int i)
{
return i*i;
}
}
}

使用：

public class DefaultController : ApiController
{
private IUserTest _userTest;
public DefaultController(IUserTest userTest)
{
_userTest = userTest;
}

// GET: api/Default/5
public int Get(int id)
{
return _userTest.GetI(id);
}

}

参考：

http://autofac.readthedocs.io/en/latest/integration/webapi.html#quick-start

https://weblogs.asp.net/shijuvarghese/dependency-injection-in-asp-net-web-api-using-autofac

https://stackoverflow.com/questions/26358287/how-do-i-resolve-web-api-controllers-using-autofac-in-a-mixed-web-api-and-mvc-ap

 https://github.com/autofac/Examples

扩展：container 需要管理起来的

http://www.cnblogs.com/niuww/p/5649632.html