c# 8 特性

属性匹配模式

    public class Teacher
    {
        public string Name { get; set; }
        public string Subject { get; set; }
        public void Deconstruct(out string name,out string subject)
        {
            name = Name;
            subject = Subject;
        }
    }


    public class Student
    {
        public Student(string name,int grade,Teacher teacher)
        {
            Name = name;
            Grade = grade;
            Teacher = teacher;
        }
        public string Name { get; set; }
        public int Grade { get; set; }
        public Teacher Teacher { get; set; }
        public void Deconstruct(out string name, out int grade, out Teacher teacher)
        {
            name = Name;
            grade = Grade;
            teacher = Teacher;
        }


        public bool Is5GradeStudent(Student student)
        {
            return student is Student(_, 5, Teacher(_, "物理"));
        }
    }


        static void Main(string[] args)
        {
            Student stu = new Student("adsfsa", 5, new Teacher()
            {
                Name = "张超",
                Subject = "物理"
            });

            bool sss= stu.Is5GradeStudent(stu);
            Console.WriteLine(sss.ToString());
        }

还可以这么写

        public bool Is5GradeStudent(Student student)
        {
            return student is { Grade: 5, Teacher: { Subject: "物理" } };
        }

        public bool Is5GradeStudent(object obj)
        {
            return obj is Student s && s is { Grade: 5, Teacher: { Subject: "物理" } };
        }