Unity IOC容器的構造函數使用筆記（不能錯過的Unity示例）

示例一，正常使用：

相關定義：

public interface ICar
{
    int Run();
}

public class BMW : ICar
{
    private int _miles = 0;

    public int Run()
    {
        return ++_miles;
    }
}

public class Ford : ICar
{
    private int _miles = 0;
    public int Run()
    {
        return ++_miles;
    }
}

public class Audi : ICar
{
    private int _miles = 0;

    public int Run()
    {
        return ++_miles;
    }

}
public class Driver
{
    private ICar _car = null;

    public Driver(ICar car)
    {
        _car = car;
    }

    public void RunCar()
    {
        Console.WriteLine("Running {0} - {1} mile ", _car.GetType().Name, _car.Run());
    }
}

使用：

var container = new UnityContainer();
container.RegisterType<ICar, BMW>();

var driver = container.Resolve<Driver>();
driver.RunCar();

我們使用Resolve來解析我們想要的調用對象，在這裡是Driver。

示例二，多個註入：

相關定義的代碼不變，將使用部分的代碼改為：

var container = new UnityContainer();
container.RegisterType<ICar, BMW>();
container.RegisterType<ICar, Audi>("LuxuryCar");

// Register Driver type            
container.RegisterType<Driver>("LuxuryCarDriver", 
                new InjectionConstructor(container.Resolve<ICar>("LuxuryCar")));

Driver driver1 = container.Resolve<Driver>();// injects BMW
driver1.RunCar();

Driver driver2 = container.Resolve<Driver>("LuxuryCarDriver");// injects Audi
driver2.RunCar();

示例三，多個構造函數參數：

相關定義：

public interface ICarKey { 
        
}

public class BMWKey : ICarKey 
{

}

public class AudiKey : ICarKey 
{

}

public class FordKey : ICarKey 
{

}

public class Driver
{
    private ICar _car = null;
    private ICarKey _key = null;

    public Driver(ICar car, ICarKey key) 
    {
        _car = car;
        _key = key;
    }

    public void RunCar()
    {
        Console.WriteLine("Running {0} with {1} - {2} mile ", _car.GetType().Name , _key.GetType().Name,  _car.Run());
    }
}

相關使用：

var container = new UnityContainer();
            
container.RegisterType<ICar, Audi>();
container.RegisterType<ICarKey, AudiKey>();

var driver = container.Resolve<Driver>();
driver.RunCar();

示例四，多個構造函數：

相關定義不變，將使用部分代碼改為：

public class Driver
{
    private ICar _car = null;
       
    [InjectionConstructor]
    public Driver(ICar car)
    {
        _car = car;
    }
    
    public Driver(string name)
    {
    }
    
    public void RunCar()
    {
        Console.WriteLine("Running {0} - {1} mile ", _car.GetType().Name, _car.Run());
    }
}

container.RegisterType<Driver>(new InjectionConstructor(new Ford()));

//or 

container.RegisterType<ICar, Ford>();
container.RegisterType<Driver>(new InjectionConstructor(container.Resolve<ICar>()));

示例五，基類型作為構造函數參數：

相關定義：

public class Driver
{
    private ICar _car = null;
    private string _name = string.Empty;

    public Driver(ICar car, string driverName)
    {
        _car = car;
        _name = driverName;
    }

    public void RunCar()
    {
        Console.WriteLine("{0} is running {1} - {2} mile ", 
                        _name, _car.GetType().Name, _car.Run());
    }
} 

相關使用：

var container = new UnityContainer();
            
container.RegisterType<Driver>(new InjectionConstructor(new object[] { new Audi(), "Steve" }));

var driver = container.Resolve<Driver>(); // Injects Audi and Steve
driver.RunCar();

完整請參考：

http://www.tutorialsteacher.com/ioc/constructor-injection-using-unity-container