Model层一小段简单的代码，哪位高手能帮小弟我理解一下~多谢【基础】

public class PubCHClassInfo
    {
        public int Id;
        public string Name = string.Empty;
        public string Nick = string.Empty;
    }

public class PubCHClassInfo
    {
            private int _id;
            public int Id
            {
                get { return _id; }
                set { _id = value; }
            }


           private string _name;
           public string Name
           {
                get{return _name;}
                set{_name = value;}
            }
    }