【EasyNetQ】- 多态发布和订阅

您可以订阅接口，然后发布该接口的实现。

我们来看一个例子。我有一个接口IAnimal和两个实现Cat和Dog：

public interface IAnimal
{
    string Name { get; set; }
}

public class Cat : IAnimal
{
    public string Name { get; set; }
    public string Meow { get; set; }
}

public class Dog : IAnimal
{
    public string Name { get; set; }
    public string Bark { get; set; }
}

我可以订阅IAnimal并接收Cat和Dog类：

bus.Subscribe<IAnimal>("polymorphic_test", @interface =>
    {
        var cat = @interface as Cat;
        var dog = @interface as Dog;

        if (cat != null)
        {
            Console.Out.WriteLine("Name = {0}", cat.Name);
            Console.Out.WriteLine("Meow = {0}", cat.Meow);
        }
        else if (dog != null)
        {
            Console.Out.WriteLine("Name = {0}", dog.Name);
            Console.Out.WriteLine("Bark = {0}", dog.Bark);
        }
        else
        {
            Console.Out.WriteLine("message was not a dog or a cat");
        }
    });

让我们发布一只猫和一只狗：

var cat = new Cat
{
    Name = "Gobbolino",
    Meow = "Purr"
};

var dog = new Dog
{
    Name = "Rover",
    Bark = "Woof"
};

bus.Publish<IAnimal>(cat);
bus.Publish<IAnimal>(dog);

请注意，我必须明确指定我发布IAnimal。EasyNetQ使用发布和订阅方法中指定的泛型类型将发布路由到订阅。