interface IAnimal
   {
       void Cry();
   }

 public class Dog : IAnimal
 {
     public void Cry()
     {
         Console.WriteLine("汪汪············");
         Console.WriteLine($"Dog:{this.GetHashCode()}");
     }

 }

void DependencyInjectionTest()
{
   

    #region 依賴接口
    //1.創建依賴注入容器
    ServiceCollection services = new ServiceCollection();
    //2.注冊相關依賴
    services.AddSingleton<IAnimal, Dog>();
    //3.獲取容器服務對象
   ServiceProvider serviceProvider =   services.BuildServiceProvider();
    //4.獲取對象 
    IAnimal animal = serviceProvider.GetRequiredService<IAnimal>();
    animal.Cry();

    #endregion
}

//調用 
DependencyInjectionTest();

//結果
汪汪············
Dog:21083178

 1 AddSingleton： 單例   創建對象在整個項目中，只有一個實例
 2 測試如下：
 3     //1.創建依賴注入容器
 4     ServiceCollection services = new ServiceCollection();
 5     //2.注冊相關依賴
 6     services.AddSingleton<IAnimal,Dog>();
 7     //3.獲取容器服務對象
 8     ServiceProvider serviceProvider = services.BuildServiceProvider();
 9     //4.獲取對象 
10     IAnimal animal = serviceProvider.GetRequiredService<IAnimal>();
11     animal.Cry();
12     IAnimal animal1 = serviceProvider.GetRequiredService<IAnimal>();
13     animal1.Cry();
14 
15 結果：
16     汪汪············
17     Dog:21083178
18     汪汪············
19     Dog:21083178

AddTransient： 多例  在每次獲取對象的時候，都重新創建一個新的對象。
測試：
   //1.創建依賴注入容器
   ServiceCollection services = new ServiceCollection();
   //2.注冊相關依賴
   //services.AddSingleton<IAnimal,Dog>();
   services.AddTransient<IAnimal,Dog>();
   //3.獲取容器服務對象
   ServiceProvider serviceProvider = services.BuildServiceProvider();
   //4.獲取對象 
   IAnimal animal = serviceProvider.GetRequiredService<IAnimal>();
   animal.Cry();
   IAnimal animal1 = serviceProvider.GetRequiredService<IAnimal>();
   animal1.Cry();

AddTransient ：在一個作用域內。保證對象是單例
測試：
//1.創建依賴注入容器
ServiceCollection services = new ServiceCollection();
//2.注冊相關依賴
//services.AddSingleton<IAnimal,Dog>();
services.AddTransient<IAnimal,Dog>();
//3.獲取容器服務對象
ServiceProvider serviceProvider = services.BuildServiceProvider();
IServiceScope serviceScope = serviceProvider.CreateScope();
{
     IAnimal animal = serviceScope.ServiceProvider.GetRequiredService<IAnimal>();
    animal.Cry();

}
{
    IAnimal animal = serviceScope.ServiceProvider.GetRequiredService<IAnimal>();
    animal.Cry();

}

結果:
汪汪············
Dog:21083178
汪汪············
Dog:55530882

結果：
汪汪············
Dog:21083178
汪汪············
Dog:55530882

public class Cat : IAnimal
{
    //屬性注入
    public Cat cat { get; set; }
    public void Cry()
    {
        Console.WriteLine($"Cat 喵喵····");
        Console.WriteLine($"Cat :{this.GetHashCode()}");
    }
}

void AutoFacDependencyInjectionTest()
{
    //1. 創建autofac容器
    ContainerBuilder containerBuilder = new ContainerBuilder();
    //2. 注冊
    containerBuilder.RegisterType<Cat>().As<IAnimal>().PropertiesAutowired();
    //3.容器服務
    IContainer container = containerBuilder.Build();
    //4.獲取對象
    IAnimal cat = container.Resolve<IAnimal>();
    cat.Cry();

}

運行結果:
Cat 喵喵····
Cat :55909147

///autofac批量注入
void AutoFacDependencyInjectionTest1()
{
    //1. 創建autofac容器
    ContainerBuilder containerBuilder = new ContainerBuilder();
    //2. 整個“項目”注冊
    containerBuilder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly())
        .AsImplementedInterfaces()  //只要有接口都實現注冊
        .PropertiesAutowired();  //依賴屬性自動注入

    //3.容器服務
    IContainer container = containerBuilder.Build();
    //4.獲取所以注冊對象的實例
    var  animals = container.Resolve<IEnumerable<IAnimal>>();
    foreach (var item in animals)
    {
        item.Cry();
    }

}
運行結果：
Cat 喵喵····
Cat :56680499
汪汪············
Dog:40362448
Sheep 咩咩····
Sheep:27717712