unity-container - 为什么 Unity 的 RegisterInstance<...> 会导致 Unity 返回多个实例？

Question

Unity 的文档中提到了 RegisterInstance<> 方法，该方法注册一个实例，以便每次调用 Resolve<> 时都会返回该特定实例。

但是，下面的示例显示每次调用 Resolve<> 时，都会返回该类型的新实例。

为什么是这样？

using System;
using System.Windows;
using Microsoft.Practices.Unity;

namespace TestUnity34
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();

            Validator validator1 = new Validator();
            IUnityContainer container = new UnityContainer();
            container.RegisterInstance<IValidator>(validator1);

            Validator validatorCopied = validator1;
            Console.WriteLine(validator1.GetHashCode()); //14421545
            Console.WriteLine(validatorCopied.GetHashCode()); //14421545

            Validator validator2 = container.Resolve<Validator>();
            Console.WriteLine(validator2.GetHashCode()); //35567111

            Validator validator3 = container.Resolve<Validator>();
            Console.WriteLine(validator3.GetHashCode()); //65066874
        }
    }

    interface IValidator
    {
        void Validate();
        string GetStatus();
    }

    public class Validator : IValidator
    {
        public void Validate() { }

        public string GetStatus() { return "test"; }
    }
}

Answer 1

您已经使用 IValidator 配置了容器，因此您必须使用 IValidator 而不是 Validator 来解决：

Validator validator1 = new Validator(); 
IUnityContainer container = new UnityContainer(); 
container.RegisterInstance<IValidator>(validator1); 
Validator validatorCopied = validator1; 
Console.WriteLine(validator1.GetHashCode());
Console.WriteLine(validatorCopied.GetHashCode());
IValidator validator2 = container.Resolve<IValidator>();            
Console.WriteLine(validator2.GetHashCode());             
IValidator validator3 = container.Resolve<IValidator>();            
Console.WriteLine(validator3.GetHashCode()); 

或者，您可以使用 Validator 保留您的注册，但您也必须使用 Validator 来解决：

Validator validator1 = new Validator();
IUnityContainer container = new UnityContainer();
container.RegisterInstance<Validator>(validator1);
Validator validatorCopied = validator1;
Console.WriteLine(validator1.GetHashCode());
Console.WriteLine(validatorCopied.GetHashCode());
Validator validator2 = container.Resolve<Validator>();
Console.WriteLine(validator2.GetHashCode());
Validator validator3 = container.Resolve<Validator>();
Console.WriteLine(validator3.GetHashCode());

Answer 2

我认为如果您使用 IValidator 作为类型参数调用 Resolve，它将按您的预期工作：

...
var validator2 = container.Resolve<IValidator>();
...