Can someone explain Microsoft Unity?

Question

I\'ve been reading the articles on MSDN about Unity (Dependency Injection, Inversion of Control), but I think I need it explained in simple terms (or simple examples). I\'m

Answer 1

I am covering most of the examples of Dependency Injection in ASP.NET Web API 2

public interface IShape
{
    string Name { get; set; }
}

public class NoShape : IShape
{
    public string Name { get; set; } = "I have No Shape";
}

public class Circle : IShape
{
    public string Name { get; set; } = "Circle";
}

public class Rectangle : IShape
{
    public Rectangle(string name)
    {
        this.Name = name;
    }

    public string Name { get; set; } = "Rectangle";
}

In DIAutoV2Controller.cs Auto Injection mechanism is used

[RoutePrefix("api/v2/DIAutoExample")]
public class DIAutoV2Controller : ApiController
{
    private string ConstructorInjected;
    private string MethodInjected1;
    private string MethodInjected2;
    private string MethodInjected3;

    [Dependency]
    public IShape NoShape { get; set; }

    [Dependency("Circle")]
    public IShape ShapeCircle { get; set; }

    [Dependency("Rectangle")]
    public IShape ShapeRectangle { get; set; }

    [Dependency("PiValueExample1")]
    public double PiValue { get; set; }

    [InjectionConstructor]
    public DIAutoV2Controller([Dependency("Circle")]IShape shape1, [Dependency("Rectangle")]IShape shape2, IShape shape3)
    {
        this.ConstructorInjected = shape1.Name + " & " + shape2.Name + " & " + shape3.Name;
    }

    [NonAction]
    [InjectionMethod]
    public void Initialize()
    {
        this.MethodInjected1 = "Default Initialize done";
    }

    [NonAction]
    [InjectionMethod]
    public void Initialize2([Dependency("Circle")]IShape shape1)
    {
        this.MethodInjected2 = shape1.Name;
    }

    [NonAction]
    [InjectionMethod]
    public void Initialize3(IShape shape1)
    {
        this.MethodInjected3 = shape1.Name;
    }

    [HttpGet]
    [Route("constructorinjection")]
    public string constructorinjection()
    {
        return "Constructor Injected: " + this.ConstructorInjected;
    }

    [HttpGet]
    [Route("GetNoShape")]
    public string GetNoShape()
    {
        return "Property Injected: " + this.NoShape.Name;
    }

    [HttpGet]
    [Route("GetShapeCircle")]
    public string GetShapeCircle()
    {
        return "Property Injected: " + this.ShapeCircle.Name;
    }

    [HttpGet]
    [Route("GetShapeRectangle")]
    public string GetShapeRectangle()
    {
        return "Property Injected: " + this.ShapeRectangle.Name;
    }

    [HttpGet]
    [Route("GetPiValue")]
    public string GetPiValue()
    {
        return "Property Injected: " + this.PiValue;
    }

    [HttpGet]
    [Route("MethodInjected1")]
    public string InjectionMethod1()
    {
        return "Method Injected: " + this.MethodInjected1;
    }

    [HttpGet]
    [Route("MethodInjected2")]
    public string InjectionMethod2()
    {
        return "Method Injected: " + this.MethodInjected2;
    }

    [HttpGet]
    [Route("MethodInjected3")]
    public string InjectionMethod3()
    {
        return "Method Injected: " + this.MethodInjected3;
    }
}

In DIV2Controller.cs everything will be injected from the Dependency Configuration Resolver class

[RoutePrefix("api/v2/DIExample")]
public class DIV2Controller : ApiController
{
    private string ConstructorInjected;
    private string MethodInjected1;
    private string MethodInjected2;
    public string MyPropertyName { get; set; }
    public double PiValue1 { get; set; }
    public double PiValue2 { get; set; }
    public IShape Shape { get; set; }

    // MethodInjected
    [NonAction]
    public void Initialize()
    {
        this.MethodInjected1 = "Default Initialize done";
    }

    // MethodInjected
    [NonAction]
    public void Initialize2(string myproperty1, IShape shape1, string myproperty2, IShape shape2)
    {
        this.MethodInjected2 = myproperty1 + " & " + shape1.Name + " & " + myproperty2 + " & " + shape2.Name;
    }

    public DIV2Controller(string myproperty1, IShape shape1, string myproperty2, IShape shape2)
    {
        this.ConstructorInjected = myproperty1 + " & " + shape1.Name + " & " + myproperty2 + " & " + shape2.Name;
    }

    [HttpGet]
    [Route("constructorinjection")]
    public string constructorinjection()
    {
        return "Constructor Injected: " + this.ConstructorInjected;
    }

    [HttpGet]
    [Route("PropertyInjected")]
    public string InjectionProperty()
    {
        return "Property Injected: " + this.MyPropertyName;
    }

    [HttpGet]
    [Route("GetPiValue1")]
    public string GetPiValue1()
    {
        return "Property Injected: " + this.PiValue1;
    }

    [HttpGet]
    [Route("GetPiValue2")]
    public string GetPiValue2()
    {
        return "Property Injected: " + this.PiValue2;
    }

    [HttpGet]
    [Route("GetShape")]
    public string GetShape()
    {
        return "Property Injected: " + this.Shape.Name;
    }

    [HttpGet]
    [Route("MethodInjected1")]
    public string InjectionMethod1()
    {
        return "Method Injected: " + this.MethodInjected1;
    }

    [HttpGet]
    [Route("MethodInjected2")]
    public string InjectionMethod2()
    {
        return "Method Injected: " + this.MethodInjected2;
    }
}

Configuring the Dependency Resolver

public static void Register(HttpConfiguration config)
{
    var container = new UnityContainer();
    RegisterInterfaces(container);
    config.DependencyResolver = new UnityResolver(container);

    // Other Web API configuration not shown.
}

private static void RegisterInterfaces(UnityContainer container)
{
    var dbContext = new SchoolDbContext();
    // Registration with constructor injection
    container.RegisterType(new InjectionConstructor(dbContext));
    container.RegisterType(new InjectionConstructor(dbContext));

    // Set constant/default value of Pi = 3.141 
    container.RegisterInstance("PiValueExample1", 3.141);
    container.RegisterInstance("PiValueExample2", 3.14);

    // without a name
    container.RegisterInstance(new NoShape());

    // with circle name
    container.RegisterType("Circle", new InjectionProperty("Name", "I am Circle"));

    // with rectangle name
    container.RegisterType("Rectangle", new InjectionConstructor("I am Rectangle"));

    // Complex type like Constructor, Property and method injection
    container.RegisterType(
        new InjectionConstructor("Constructor Value1", container.Resolve("Circle"), "Constructor Value2", container.Resolve()),
        new InjectionMethod("Initialize"),
        new InjectionMethod("Initialize2", "Value1", container.Resolve("Circle"), "Value2", container.Resolve()),
        new InjectionProperty("MyPropertyName", "Property Value"),
        new InjectionProperty("PiValue1", container.Resolve("PiValueExample1")),
        new InjectionProperty("Shape", container.Resolve("Rectangle")),
        new InjectionProperty("PiValue2", container.Resolve("PiValueExample2")));
}