为什么我的班级没有通过反思被接受？

Question

我正在尝试创建一个单元测试来验证我的加载AutoMapper配置的方法是否正常工作.我加载AutoMapper配置的想法是将配置调用放在具有以下接口的类中:

public interface IEntityMapConfiguration
{
    void ConfigureMapping();
}

要动态加载它们,我有以下加载器类

public class EntityMapLoader
{
    public static void LoadEntityMappings()
    {
        // Load all IEntityMapConfiguration classes via reflection
        var types = AppDomain.CurrentDomain
                             .GetAssemblies()
                             .SelectMany(x => x.GetTypes())
                             .Where(x => x.IsSubclassOf(typeof(IEntityMapConfiguration)))
                             .Select(x => x as IEntityMapConfiguration)
                             .ToList();

        foreach (var config in types)
            config.ConfigureMapping();
    }
}

为了验证这一点,我创建了以下单元测试

public class UnitTestEntityViewModel
{
    public int Id { get; set; }
    public int Text2 { get; set; }
}

public class TestProjectionMapping : IEntityMapConfiguration
{
    public void ConfigureMapping()
    {
        Mapper.CreateMap<UnitTestEntity, UnitTestEntityViewModel>()
            .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.Id))
            .ForMember(dest => dest.Text2, opt => opt.MapFrom(src => src.Text));
    }
}

[TestClass]
public class AutomapperConfigurationTests
{
    [TestMethod]
    public void Loader_Loads_All_Configurations_In_Assembly()
    {
        // Setup
        UnitTestEntity entity = new UnitTestEntity { Id = 2, Text = "Test 1234" };

        // Act
        EntityMapLoader.LoadEntityMappings();

        // Verify
        UnitTestEntityViewModel result = Mapper.Map<UnitTestEntity, UnitTestEntityViewModel>(entity);
        Assert.AreEqual(entity.Id, result.Id, "View model's ID value did not match");
        Assert.AreEqual(entity.Text, result.Text2, "View model's text value did not match");
    }
}

问题是这个单元测试失败了,因为它没有拿起我的TestProjectionMapping课,我无法弄清楚原因.在我LoadEntityMappings()的types列表中,计数为零.我已经验证我的测试程序集是从中返回的AppDomain.CurrentDomain.GetAssemblies().

我确定我做的事情显然是错的,但我找不到.有任何想法吗？

---

编辑:我更新了我的LoadentityMappings()方法:

    public static void LoadEntityMappings()
    {
        // Load all IEntityMapConfiguration classes via reflection
        var types = AppDomain.CurrentDomain
                             .GetAssemblies()
                             .SelectMany(x => x.GetTypes())
                             .Where(x => x.GetInterfaces().Contains(typeof(IEntityMapConfiguration)))
                             .Select(x => x as IEntityMapConfiguration)
                             .ToList();

        foreach (var config in types)
            config.ConfigureMapping();
    }

这仍然是失败的.声明(没有最终选择)正在返回我的TestProjectionMapping课程,但是x as IEntityMapconfiguration失败了.在我键入的调试器中,我(IEntityMapConfiguration)types[0]收到以下错误:

Cannot cast 'types[0]' (which has an actual type of 'System.RuntimeType') to 'MyJobLeads.DomainModel.EntityMapping.IEntityMapConfiguration'

在观察列表中输入以供参考types[0]:

types[0] {Name = "TestProjectionMapping" FullName = "MyJobLeads.Tests.TestProjectionMapping"} System.Type {System.RuntimeType}

还有,types[0] is IEntityMapConfiguration是false

我不知道为什么我不能做这个演员,任何想法？

Answer 1

您无法使用Type.IsSubclassOf查看类型是否实现接口.您必须使用Type.IsAssignableFrom(或者您可以使用is IEntityMapConfiguration或Type.GetInterfaces然后查看结果序列是否包含typeof(IEntityMapConfiguration).

现在想想为什么你不能Type.IsSubclassOf用来看看是否Type实现了一个接口.因为我们没有说实现接口的类是该接口的子类; 相反,我们说它实现了接口,我们保留它的基类的子类(object或者ValueType除非指定了一个).

顺便说一句,这在文档中明确说明Type.IsSubclassOf:

该IsSubclassOf方法不能用于确定接口是否从另一个接口派生,或者类是否实现接口.