StructureMap 在请求实例时向构造函数提供字符串参数

Question

您好，在 Autofac 我可以这样做：

public class Service1_Client
{
    private const string ServiceName = "Service1";
    Func<string, RabitMqClient> _clientFunc;

    public Service1_Client(Func<string, RabitMqClient> clientFunc) 
    { 
         _clientFunc = clientFunc;
    }

    public IList<object> GetData()
    {
        return _clientFunc(this.ServiceName).Get<IList<object>>();               
    }
}

public class Service2_Client
{
    private const string ServiceName = "Service2";
    Func<string, RabitMqClient> _clientFunc;

    public Service2_Client(Func<string, RabitMqClient> clientFunc) 
    { 
         _clientFunc = clientFunc;
    }

    public IList<object> GetData()
    {
        return _clientFunc(this.ServiceName).Get<IList<object>>();               
    }
}

public class RabitMqClient
{
    private IConnectionFactory _connectionFactory;
    private string _baseServiceName;
    public RabitMqClient(IConnectionFactory connectionFactory, string baseServiceName)
    {
        _connectionFactory = connectionFactory;
        _baseServiceName = baseServiceName;
    }

    public TResult Get<TResult>()
    {
        string topicName = this.GetTopicName();
        ///Connect to the channel that uses the topic and ask for data...
    }

    private string GetTopicNAme()
    {
        /// this should be an algoritam for getting the topic from the speccified baseServiceName (I have omitted the details)
        return this._baseServiceName;
    }     
}

现在解释： 基本上我有一个依赖于 2 个参数的类（RabitMqClient）：

1. connectionFactory (IConnectionFactory)
2. baseServiceName（字符串）

这些参数用于连接到 RabbitMq 服务器。 现在我使用 RabbitMq 中的 Topics 来多样化服务，为了得到正确的 Topic，使用了字符串参数 baseServiceName。 调用方 (Service1_Client, Service2_Client) 应提供字符串参数 baseServiceName。

在 Autofac 我可以像这样注册这个类：

builder.Register((context, parameters) =>
{
    var param = parameters.First() as Autofac.TypedParameter;
    return new HcRabbitMqClient(
        context.Resolve<IConnectionFactory>(),param.Value.ToString());
}).AsSelf().InstancePerDependency();

这告诉 Autofac，当请求这个类时，让 Autofac 解析第一个参数，但调用者将在调用站点提供第二个（字符串）参数。然后将这个字符串参数放入参数值中。 this的用法可以看上面的代码（Service1_Client,Service2_Client）GetData()方法；

如何在 StructureMap 中做到这一点？

Answer 1

扩展工厂模式怎么样？

public interface IRabitMqClientFactory
{
    IRabitMqClientFactory Create(string baseServiceName);
}

public class RabitMqClientFactory : IRabitMqClientFactory
{
    public RabitMqClientFactory(IConnectionFactory connectionFactory){
        _connectionFactory = connectionFactory;
    }

    public IRabitMqClientFactory Create(string baseServiceName)
    {
        _baseServiceName = baseServiceName;
    }
}

然后简单地

public class Service1_Client
{
    private const string ServiceName = "Service1";
    private RabbitMqClient _rabbitMqClient;

    public Service1_Client(IRabitMqClientFactory rabitMqClientFactory) 
    { 
         _rabbitMqClient = rabitMqClientFactory.Create(ServiceName);
    }

    public IList<object> GetData()
    {
        return _rabbitMqClient.Get<IList<object>>();               
    }
}

它也比 IoC 中的复杂逻辑更具可读性。

Answer 2

试试这个
For<Func<string, RabitMqClient>>().Use(cstr => new RabitMqClient(cstr));