public class User
    {
        public User()
        {
            Console.WriteLine($"{this.GetType().Name}被构造");
        }
        public int Id { get; set; }
        public string Name { get; set; }

        public string ClassID;
    }

//常规写法赋值
{
                User user = new User();
                user.Id = 123;
                user.Name = "张三";
                user.ClassID = "1";
                Console.WriteLine($"User.Name={user.Name}");
                Console.WriteLine($"User.ClassID={user.ClassID}");
                Console.WriteLine($"User.Id={user.Id}");
            }
//利用反射动态赋值
 {
                Type type = typeof(User);  //获取类型
                object a = Activator.CreateInstance(type);   //创建对象
                foreach (var Prop in type.GetProperties())//GetProperties获取属性
                {
                    Console.WriteLine($"{type.Name}.{Prop.Name}={Prop.GetValue(a)}");
                    if (Prop.Name.Equals("Id"))
                    {
                        Prop.SetValue(a, 213);//设置值
                    }
                    else if (Prop.Name.Equals("Name"))
                    {
                        Prop.SetValue(a,"张三");
                    }
                    Console.WriteLine($"{type.Name}.{Prop.Name}={Prop.GetValue(a)}");//获取值
                }
                foreach (var Field in type.GetFields())//GetFields获取字段
                {
                    Console.WriteLine($"{type.Name}.{Field.Name}={Field.GetValue(a)}");
                    if (Field.Name.Equals("ClassID"))
                    {
                        Field.SetValue(a, "213");
                    }          
                    Console.WriteLine($"{type.Name}.{Field.Name}={Field.GetValue(a)}");
                }
            }