我有一个泛型类在我的项目与派生类。

public class GenericClass<T> : GenericInterface<T>
{
}

public class Test : GenericClass<SomeType>
{
}

是否有任何方法可以查明Type对象是否派生自GenericClass?

t.IsSubclassOf(typeof(GenericClass<>))

不管用。


当前回答

简单的解决方案:只需创建并添加第二个非泛型接口到泛型类:

public interface IGenericClass
{
}

public class GenericClass<T> : GenericInterface<T>, IGenericClass
{
}

然后用is as IsAssignableFrom等任何你喜欢的方式检查。

if (thing is IGenericClass)
{
    // Do work
{

显然,只有当您能够编辑泛型类(OP似乎具有这种能力)时才有可能,但它比使用神秘的扩展方法更优雅、更可读。

其他回答

在fir3rpho3nixx和David Schmitt的出色回答的基础上,我修改了他们的代码,并添加了ShouldInheritOrImplementTypedGenericInterface测试(最后一个)。

    /// <summary>
    /// Find out if a child type implements or inherits from the parent type.
    /// The parent type can be an interface or a concrete class, generic or non-generic.
    /// </summary>
    /// <param name="child"></param>
    /// <param name="parent"></param>
    /// <returns></returns>
    public static bool InheritsOrImplements(this Type child, Type parent)
    {
        var currentChild = parent.IsGenericTypeDefinition && child.IsGenericType ? child.GetGenericTypeDefinition() : child;

        while (currentChild != typeof(object))
        {
            if (parent == currentChild || HasAnyInterfaces(parent, currentChild))
                return true;

            currentChild = currentChild.BaseType != null && parent.IsGenericTypeDefinition && currentChild.BaseType.IsGenericType
                                ? currentChild.BaseType.GetGenericTypeDefinition()
                                : currentChild.BaseType;

            if (currentChild == null)
                return false;
        }
        return false;
    }

    private static bool HasAnyInterfaces(Type parent, Type child)
    {
        return child.GetInterfaces().Any(childInterface =>
            {
                var currentInterface = parent.IsGenericTypeDefinition && childInterface.IsGenericType
                    ? childInterface.GetGenericTypeDefinition()
                    : childInterface;

                return currentInterface == parent;
            });

    }

    [Test]
    public void ShouldInheritOrImplementNonGenericInterface()
    {
        Assert.That(typeof(FooImplementor)
            .InheritsOrImplements(typeof(IFooInterface)), Is.True);
    }

    [Test]
    public void ShouldInheritOrImplementGenericInterface()
    {
        Assert.That(typeof(GenericFooBase)
            .InheritsOrImplements(typeof(IGenericFooInterface<>)), Is.True);
    }

    [Test]
    public void ShouldInheritOrImplementGenericInterfaceByGenericSubclass()
    {
        Assert.That(typeof(GenericFooImplementor<>)
            .InheritsOrImplements(typeof(IGenericFooInterface<>)), Is.True);
    }

    [Test]
    public void ShouldInheritOrImplementGenericInterfaceByGenericSubclassNotCaringAboutGenericTypeParameter()
    {
        Assert.That(new GenericFooImplementor<string>().GetType()
            .InheritsOrImplements(typeof(IGenericFooInterface<>)), Is.True);
    }

    [Test]
    public void ShouldNotInheritOrImplementGenericInterfaceByGenericSubclassNotCaringAboutGenericTypeParameter()
    {
        Assert.That(new GenericFooImplementor<string>().GetType()
            .InheritsOrImplements(typeof(IGenericFooInterface<int>)), Is.False);
    }

    [Test]
    public void ShouldInheritOrImplementNonGenericClass()
    {
        Assert.That(typeof(FooImplementor)
            .InheritsOrImplements(typeof(FooBase)), Is.True);
    }

    [Test]
    public void ShouldInheritOrImplementAnyBaseType()
    {
        Assert.That(typeof(GenericFooImplementor<>)
            .InheritsOrImplements(typeof(FooBase)), Is.True);
    }

    [Test]
    public void ShouldInheritOrImplementTypedGenericInterface()
    {
        GenericFooImplementor<int> obj = new GenericFooImplementor<int>();
        Type t = obj.GetType();

        Assert.IsTrue(t.InheritsOrImplements(typeof(IGenericFooInterface<int>)));
        Assert.IsFalse(t.InheritsOrImplements(typeof(IGenericFooInterface<String>)));
    } 

这些都可以用linq轻松完成。这将找到泛型基类GenericBaseType的子类的任何类型。

    IEnumerable<Type> allTypes = Assembly.GetExecutingAssembly().GetTypes();

    IEnumerable<Type> mySubclasses = allTypes.Where(t => t.BaseType != null 
                                                            && t.BaseType.IsGenericType
                                                            && t.BaseType.GetGenericTypeDefinition() == typeof(GenericBaseType<,>));

更新后的答案

这个方法检查typeA是否等于、继承(class: class)、实现(class: interface)或扩展(interface: interface) typeB。它接受泛型和非泛型接口和类。

public static bool Satisfies(Type typeA, Type typeB)
{
    var types = new List<Type>(typeA.GetInterfaces());
    for (var t = typeA; t != null; t = t.BaseType)
    {
        types.Add(t);
    }
    return types.Any(t =>
        t == typeB ||
            t.IsGenericType && (t.GetGenericTypeDefinition() == typeB));
}

在下面使用,它通过了76个测试中的74个@Xav987的答案(它没有通过测试'68-3'和'69-3',但我认为这些测试暗示List<长颈鹿>是List<动物>的子类,我不认为它是。例如,List<长颈鹿>不能施放到List<动物>,参见https://stackoverflow.com/a/9891849/53252。)

public static bool IsSubClassOfGeneric(this Type typeA, Type typeB)
{
    if (typeA == typeB)
    {
        return false;
    }
    return Satisfies(typeA, typeB);
}

例子:

using System.Collections;
using System.Numerics;

void ShowSatisfaction(Type typeA, Type typeB)
{
    var satisfied = Satisfies(typeA, typeB);
    Console.WriteLine($"{satisfied}: [{typeA}]  satisfies  [{typeB}]");
}

ShowSatisfaction(typeof(object), typeof(string));
ShowSatisfaction(typeof(string), typeof(object));
ShowSatisfaction(typeof(string), typeof(IEnumerable));
ShowSatisfaction(typeof(string), typeof(IEnumerable<>));
ShowSatisfaction(typeof(string), typeof(IEnumerable<char>));
ShowSatisfaction(typeof(string), typeof(IEnumerable<int>));
ShowSatisfaction(typeof(int), typeof(object));
ShowSatisfaction(typeof(int), typeof(IComparable));
ShowSatisfaction(typeof(IReadOnlyDictionary<,>), typeof(IReadOnlyCollection<>));
ShowSatisfaction(typeof(bool), typeof(INumber<>));
ShowSatisfaction(typeof(int), typeof(INumber<>));
ShowSatisfaction(typeof(IBinaryInteger<>), typeof(IShiftOperators<,>));
ShowSatisfaction(typeof(IBinaryInteger<int>), typeof(IShiftOperators<,>));
ShowSatisfaction(typeof(IBinaryInteger<int>), typeof(IShiftOperators<int, int>));

输出:

False: [System.Object]  satisfies  [System.String]
True: [System.String]  satisfies  [System.Object]
True: [System.String]  satisfies  [System.Collections.IEnumerable]
True: [System.String]  satisfies  [System.Collections.Generic.IEnumerable`1[T]]
True: [System.String]  satisfies  [System.Collections.Generic.IEnumerable`1[System.Char]]
False: [System.String]  satisfies  [System.Collections.Generic.IEnumerable`1[System.Int32]]
True: [System.Int32]  satisfies  [System.Object]
True: [System.Int32]  satisfies  [System.IComparable]
True: [System.Collections.Generic.IReadOnlyDictionary`2[TKey,TValue]]  satisfies  [System.Collections.Generic.IReadOnlyCollection`1[T]]
False: [System.Boolean]  satisfies  [System.Numerics.INumber`1[TSelf]]
True: [System.Int32]  satisfies  [System.Numerics.INumber`1[TSelf]]
True: [System.Numerics.IBinaryInteger`1[TSelf]]  satisfies  [System.Numerics.IShiftOperators`2[TSelf,TResult]]
True: [System.Numerics.IBinaryInteger`1[System.Int32]]  satisfies  [System.Numerics.IShiftOperators`2[TSelf,TResult]]
True: [System.Numerics.IBinaryInteger`1[System.Int32]]  satisfies  [System.Numerics.IShiftOperators`2[System.Int32,System.Int32]]

INumber<>的例子来自。net 7预览5。

以前的回答

它可能是多余的,但我使用如下扩展方法。它们检查接口和子类。它还可以返回具有指定泛型定义的类型。

例如,对于问题中的例子,它可以测试泛型接口以及泛型类。返回的类型可以与GetGenericArguments一起使用,以确定泛型参数类型是“SomeType”。

/// <summary>
/// Checks whether this type has the specified definition in its ancestry.
/// </summary>   
public static bool HasGenericDefinition(this Type type, Type definition)
{
    return GetTypeWithGenericDefinition(type, definition) != null;
}

/// <summary>
/// Returns the actual type implementing the specified definition from the
/// ancestry of the type, if available. Else, null.
/// </summary>
public static Type GetTypeWithGenericDefinition(this Type type, Type definition)
{
    if (type == null)
        throw new ArgumentNullException("type");
    if (definition == null)
        throw new ArgumentNullException("definition");
    if (!definition.IsGenericTypeDefinition)
        throw new ArgumentException(
            "The definition needs to be a GenericTypeDefinition", "definition");

    if (definition.IsInterface)
        foreach (var interfaceType in type.GetInterfaces())
            if (interfaceType.IsGenericType
                && interfaceType.GetGenericTypeDefinition() == definition)
                return interfaceType;

    for (Type t = type; t != null; t = t.BaseType)
        if (t.IsGenericType && t.GetGenericTypeDefinition() == definition)
            return t;

    return null;
}

简单的解决方案:只需创建并添加第二个非泛型接口到泛型类:

public interface IGenericClass
{
}

public class GenericClass<T> : GenericInterface<T>, IGenericClass
{
}

然后用is as IsAssignableFrom等任何你喜欢的方式检查。

if (thing is IGenericClass)
{
    // Do work
{

显然,只有当您能够编辑泛型类(OP似乎具有这种能力)时才有可能,但它比使用神秘的扩展方法更优雅、更可读。

添加到@jaredpar的答案中,下面是我用来检查接口的方法:

public static bool IsImplementerOfRawGeneric(this Type type, Type toCheck)
{
    if (toCheck.GetTypeInfo().IsClass)
    {
        return false;
    }

    return type.GetInterfaces().Any(interfaceType =>
    {
        var current = interfaceType.GetTypeInfo().IsGenericType ?
                    interfaceType.GetGenericTypeDefinition() : interfaceType;
        return current == toCheck;
    });
}

public static bool IsSubTypeOfRawGeneric(this Type type, Type toCheck)
{
    return type.IsInterface ?
          IsImplementerOfRawGeneric(type, toCheck)
        : IsSubclassOfRawGeneric(type, toCheck);
}

Ex:

Console.WriteLine(typeof(IList<>).IsSubTypeOfRawGeneric(typeof(IList<int>))); // true