.NET/C#如何判断某个类是否是泛型类型或泛型接口的子类型详解

if (instance is Foo || instance is IFoo)
{
}

if (typeof(Foo).IsAssignableFrom(type) || typeof(IFoo).IsAssignableFrom(type))
{
}

if (type.IsSubClassOf(typeof(Foo)))
{
}

public static bool HasImplementedRawGeneric(this Type type, Type generic)
{
 // 遍历类型实现的所有接口，判断是否存在某个接口是泛型，且是参数中指定的原始泛型的实例。
 return type.GetInterfaces().Any(x => generic == (x.IsGenericType ? x.GetGenericTypeDefinition() : x));
}

public static bool IsSubClassOfRawGeneric([NotNull] this Type type, [NotNull] Type generic)
{
 if (type == null) throw new ArgumentNullException(nameof(type));
 if (generic == null) throw new ArgumentNullException(nameof(generic));

 while (type != null && type != typeof(object))
 {
 isTheRawGenericType = IsTheRawGenericType(type);
 if (isTheRawGenericType) return true;
 type = type.BaseType;
 }

 return false;

 bool IsTheRawGenericType(Type test)
 => generic == (test.IsGenericType ? test.GetGenericTypeDefinition() : test);
}

/// <summary>
/// 判断指定的类型 <paramref name="type"/> 是否是指定泛型类型的子类型，或实现了指定泛型接口。
/// </summary>
/// <param name="type">需要测试的类型。</param>
/// <param name="generic">泛型接口类型，传入 typeof(IXxx<>)</param>
/// <returns>如果是泛型接口的子类型，则返回 true，否则返回 false。</returns>
public static bool HasImplementedRawGeneric([NotNull] this Type type, [NotNull] Type generic)
{
 if (type == null) throw new ArgumentNullException(nameof(type));
 if (generic == null) throw new ArgumentNullException(nameof(generic));

 // 测试接口。
 var isTheRawGenericType = type.GetInterfaces().Any(IsTheRawGenericType);
 if (isTheRawGenericType) return true;

 // 测试类型。
 while (type != null && type != typeof(object))
 {
 isTheRawGenericType = IsTheRawGenericType(type);
 if (isTheRawGenericType) return true;
 type = type.BaseType;
 }

 // 没有找到任何匹配的接口或类型。
 return false;

 // 测试某个类型是否是指定的原始接口。
 bool IsTheRawGenericType(Type test)
 => generic == (test.IsGenericType ? test.GetGenericTypeDefinition() : test);
}