Devexpress TreeList控件无法显示数据问题的解决

原来是没有给实体类设置get,set,实体类要这样写

public class Student
    {
        public long Id { get; set; }
        public string Name { get; set; }
        public string Sex { get; set; }
        public long Pid { get; set; }
        public Student(int id, string name, string sex, long pid)
        {
            Id = id;
            Name = name;
            Sex = sex;
            Pid = pid;
        }
    }