configuration - 统一 : Specify Dependency name during configuration

Question

我有以下片段:

static void Main(string[] args) {
    var container = new UnityContainer();
    container.RegisterType<IConnection, SerialPortConnection>("SerialConnection");
    container.RegisterType<IConnection, ParallelPortConnection>("ParallelConnection");
    container.RegisterType<Device>("ParallelDevice");
    container.RegisterType<Device>("SerialDevice");
}

我要注册类型 Device在两个不同的名称下，以便根据请求的名称 Device实例将使用适当的 Connection 初始化.以下是解决此问题的一种方法，仅用于演示:

public class ParallelDevice : Device {
    public ParallelDevice([Dependency("ParallelConnection")] IConnection connection) : base(connection) {}
}
public class SerialDevice : Device {
    public SerialDevice([Dependency("ParallelConnection")] IConnection connection) : base(connection) {}
}

// and register with 
container.RegisterType<Device, ParallelDevice>("ParallelDevice");
container.RegisterType<Device, SerialDevice>("SerialDevice");

有一个更好的方法吗？就像是:

container.RegisterType<Device>("ParallelDevice").UseDependencyNames("ParallelConnection");

Answer 1

您应该努力使您的代码不受 DI 容器特定的影响。在这种情况下，您可以简单地定义您的设备，而无需引用 Unity。这里以 SerialDevice 为例，但 ParallelDevice 类完全相似:

public class SerialDevice : Device
{
    public SerialDevice(IConnection connection)
        : base(connection) { }
}

你可以像这样配置你的容器:

container.RegisterType<IConnection, SerialPortConnection>("SerialConnection");
container.RegisterType<IConnection, ParallelPortConnection>("ParallelConnection");
container.RegisterType<Device, SerialDevice>("SerialDevice",
    new InjectionConstructor(new ResolvedParameter<IConnection>("SerialConnection")));
container.RegisterType<Device, ParallelDevice>("ParallelDevice",
    new InjectionConstructor(new ResolvedParameter<IConnection>("ParallelConnection")));

这将允许您像这样解析两个设备对象:

var serialDevice = container.Resolve<Device>("SerialDevice");
var parallelDevice = container.Resolve<Device>("ParallelDevice");