Question

在DryIoc中，如何将字符串参数传递给工厂方法？

在Wiki中，有关于如何传递另一个注册类的示例，但我似乎无法弄清楚如何传递字符串。

鉴于以下内容：

public interface MyInterface
{
}

public class MyImplementationA : MyInterface
{
    public MyImplementationA(string value) { }
}

public class Factory
{
    public MyInterface Create(string value)
    {
        return new MyImplementationA(value);
    }
}

public class MyService1
{
    public MyService1(MyInterface implementation) {  }
}

class Program
{
    static void Main(string[] args)
    {
        var c = new Container();
        c.Register<Factory>(Reuse.Singleton);
        c.Register<MyInterface>(Reuse.Singleton, made: Made.Of(r => ServiceInfo.Of<Factory>(),
            f => f.Create("some value") //How do I pass a string to the factory method?
        ));

        c.Register<MyService1>();

        var a = c.Resolve<MyService1>();
    }
}

Answer 1

如果要为特定依赖项注入字符串值，可以这样做：

c.Register<Factory>(Reuse.Singleton);
c.Register<MyInterface>(Reuse.Singleton, 
    made: Made.Of(r => ServiceInfo.Of<Factory>(),
           // Arg.Index(0) is a placeholder for value, like {0} in string.Format("{0}", "blah")
            f => f.Create(Arg.Index<string>(0)), 
            requestIgnored => "blah or something else"));

这里是来自how to provide Consumer type to log4net logger上的wiki的类似示例。

另一种方式是c.RegisterInstance("value of blah", serviceKey: ConfigKeys.Blah);。

或者您可以使用FactoryMethod注册来注册字符串提供程序，以获取计算，懒惰或任何值。为清晰起见，归因注册的示例：

[Export, AsFactory]
public class Config
{
    [Export("config.blah")]
    public string GetBlah()
    { 
      // retrieve value and
      return result;    
    }
}

// In composition root:
using DryIoc.MefAttributedModel;
// ...
var c = new Container().WithAttributedModel();
c.RegisterExports(typeof(Config), /* other exports */);

带字符串参数的工厂方法

1 个答案: