类是否继承某个类

// IsSubclassOf TestChild是否为TestParent的子类
typeof(TestChild).IsSubclassOf(typeof(TestParent))

// IsAssignableFrom TestParent是否为TestChild的父类
typeof(TestParent).IsAssignableFrom(typeof(TestChild))

类是否实现某个接口

typeof(TestClass).GetInterface(typeof(InterfaceClass).Name)

typeof(TestClass).GetInterface("InterfaceClass")

Demo

private void Print(Type typea, Type typeb)
        {
            if (typeb.IsInterface)
            {
                // 是否实现了接口判断
                Console.WriteLine(string.Format("{0}实现了接口{1} {0} GetInterface {1} ====> {2}",
                typea.Name,
                typeb.Name,
                typea.GetInterface(typeb.Name) != null
                ));
            }
            else
            {
                Console.WriteLine(string.Format("{0}是{1}的子类 {0} IsSubclassOf {1} ====> {2}",
                typea.Name,
                typeb.Name,
                typea.IsSubclassOf(typeb)
                ));

                Console.WriteLine(string.Format("{0}是{1}的父类 {0} IsAssignableFrom {1} ====> {2}",
                typeb.Name,
                typea.Name,
                typeb.IsAssignableFrom(typea)
                ));
            }
        }