如何确定类型是否实现特定的泛型接口类型

通过使用来自tcks的答案,还可以通过以下LINQ查询来完成:

bool isBar = foo.GetType().GetInterfaces().Any(x =>
  x.IsGenericType &&
  x.GetGenericTypeDefinition() == typeof(IBar<>));

您必须遍历继承树,找到树中每个类的所有接口,然后比较 typeof(IBar<>) 呼叫的结果 Type.GetGenericTypeDefinition 如果 接口是通用的。当然,这有点痛苦。

见 this answer 和 these ones 更多信息和代码。

public interface IFoo<T> : IBar<T> {}
public class Foo : IFoo<Foo> {}

var implementedInterfaces = typeof( Foo ).GetInterfaces();
foreach( var interfaceType in implementedInterfaces ) {
    if ( false == interfaceType.IsGeneric ) { continue; }
    var genericType = interfaceType.GetGenericTypeDefinition();
    if ( genericType == typeof( IFoo<> ) ) {
        // do something !
        break;
    }
}

作为辅助方法扩展

public static bool Implements<I>(this Type type, I @interface) where I : class
{
    if(((@interface as Type)==null) || !(@interface as Type).IsInterface)
        throw new ArgumentException("Only interfaces can be 'implemented'.");

    return (@interface as Type).IsAssignableFrom(type);
}

示例用法:

var testObject = new Dictionary<int, object>();
result = testObject.GetType().Implements(typeof(IDictionary<int, object>)); // true!

您必须检查通用接口的构造类型。

你必须这样做:

foo is IBar<String>

因为 IBar<String> 表示构造的类型。你必须这样做的原因是如果 T 在您的检查中没有定义,编译器不知道您的意思是 IBar<Int32> 或 IBar<SomethingElse> .

我正在使用稍微简单一点的@genericProgrammers扩展方法:

public static bool Implements<TInterface>(this Type type) where TInterface : class {
    var interfaceType = typeof(TInterface);

    if (!interfaceType.IsInterface)
        throw new InvalidOperationException("Only interfaces can be implemented.");

    return (interfaceType.IsAssignableFrom(type));
}

用途:

    if (!featureType.Implements<IFeature>())
        throw new InvalidCastException();

首先 public class Foo : IFoo<T> {} 不编译,因为您需要指定一个类而不是t,但假设您执行类似的操作 public class Foo : IFoo<SomeClass> {}

如果你这样做

Foo f = new Foo();
IBar<SomeClass> b = f as IBar<SomeClass>;

if(b != null)  //derives from IBar<>
    Blabla();

为了完全处理类型系统,我认为您需要处理递归,例如 IList<T> : ICollection<T> : IEnumerable<T> 如果没有它你就不会知道 IList<int> 最终实现 IEnumerable<> .

    /// <summary>Determines whether a type, like IList&lt;int&gt;, implements an open generic interface, like
    /// IEnumerable&lt;&gt;. Note that this only checks against *interfaces*.</summary>
    /// <param name="candidateType">The type to check.</param>
    /// <param name="openGenericInterfaceType">The open generic type which it may impelement</param>
    /// <returns>Whether the candidate type implements the open interface.</returns>
    public static bool ImplementsOpenGenericInterface(this Type candidateType, Type openGenericInterfaceType)
    {
        Contract.Requires(candidateType != null);
        Contract.Requires(openGenericInterfaceType != null);

        return
            candidateType.Equals(openGenericInterfaceType) ||
            (candidateType.IsGenericType && candidateType.GetGenericTypeDefinition().Equals(openGenericInterfaceType)) ||
            candidateType.GetInterfaces().Any(i => i.IsGenericType && i.ImplementsOpenGenericInterface(openGenericInterfaceType));

    }

如果您想要一个支持通用基类型和接口的扩展方法,我已经扩展了sduplooy的答案:

    public static bool InheritsFrom(this Type t1, Type t2)
    {
        if (null == t1 || null == t2)
            return false;

        if (null != t1.BaseType &&
            t1.BaseType.IsGenericType &&
            t1.BaseType.GetGenericTypeDefinition() == t2)
        {
            return true;
        }

        if (InheritsFrom(t1.BaseType, t2))
            return true;

        return
            (t2.IsAssignableFrom(t1) && t1 != t2)
            ||
            t1.GetInterfaces().Any(x =>
              x.IsGenericType &&
              x.GetGenericTypeDefinition() == t2);
    }

方法检查类型是否继承或实现泛型类型:

   public static bool IsTheGenericType(this Type candidateType, Type genericType)
    {
        return
            candidateType != null && genericType != null &&
            (candidateType.IsGenericType && candidateType.GetGenericTypeDefinition() == genericType ||
             candidateType.GetInterfaces().Any(i => i.IsGenericType && i.GetGenericTypeDefinition() == genericType) ||
             candidateType.BaseType != null && candidateType.BaseType.IsTheGenericType(genericType));
    }

以下内容不应该有任何问题:

bool implementsGeneric = (anObject.Implements("IBar`1") != null);

如果您想为IBAR查询提供一个特定的泛型类型参数,那么对于额外的学分,您可以捕获含糊不清的matchException。