最近在学习C#有好多知识都不了解，请各路高手帮忙指点（FeatureModel.cs）

请高手帮忙添加注释！
using System;
using System.Data.SqlClient;
using System.Data;
using System.Collections.Generic;

namespace kms.Models
{
    public class FeatureModel:BaseModel
    {
        protected string tablename = "feature";

        public int id;

        public string feature_name;

        public List<FeatureModel> list()
        {
            string sql = "SELECT id,feature_name FROM " + this.tablename + " ORDER BY id DESC";
            SqlDataReader sdr = getReader(sql, null);
            List<FeatureModel> flist = new List<FeatureModel>();
            if (sdr.HasRows)
            {
                while (sdr.Read())
                {
                    FeatureModel mm = new FeatureModel();
                    mm.id = Convert.ToInt32(sdr["id"].ToString());
                    mm.feature_name = sdr["feature_name"].ToString();
                    flist.Add(mm);
                }
            }
            sdr.Close();
            return flist;
        }

        public void delete(int id)
        {
            string sql = "DELETE FROM "+this.tablename+" WHERE id=@id";
            SqlParameter[] parArray = { 
                CommonLb.makeParam("@id",SqlDbType.Int,id)
            };
            excuteQuery(sql, parArray);
        }

        public int add(string feature_name)
        {
            string sql = "INSERT INTO " + this.tablename + "(feature_name) VALUES(@feature_name)";
            SqlParameter[] parArray = { 
                CommonLb.makeParam("@feature_name",SqlDbType.NVarChar,feature_name)
            };
            return excuteQuery(sql, parArray);
        }
        public FeatureModel getOne(int id)
        {
            if (id <= 0)
                return null;
            FeatureModel mm = new FeatureModel();
            SqlParameter[] parArray = { 
                CommonLb.makeParam("@id",SqlDbType.Int,id)
            };
            string sql = "SELECT TOP 1 id,feature_name FROM " + this.tablename + " WHERE id=@id";
            SqlDataReader sdr = getReader(sql, parArray);
            if (sdr.HasRows)
            {
                sdr.Read();
                mm.feature_name = sdr["feature_name"].ToString();
                mm.id = Convert.ToInt32(sdr["id"].ToString());
            }
            sdr.Close();
            return mm;
        }

        public int update(int id, string feature_name)
        {
            string sql = "UPDATE " + this.tablename + " SET feature_name=@feature_name WHERE id=@id";
            SqlParameter[] parArray = { 
                CommonLb.makeParam("@feature_name",SqlDbType.NVarChar,feature_name),
                CommonLb.makeParam("@id",SqlDbType.Int,id)
            };
            return excuteQuery(sql, parArray);
        }
    }
} --------------------编程问答-------------------- using System;
using System.Data.SqlClient;
using System.Data;
using System.Collections.Generic;引入命令空间

namespace kms.Models
{
  public class FeatureModel:BaseModel定义类
  {
  protected string tablename = "feature";定义成员

  public int id;
定义成员
  public string feature_name;定义成员

  public List<FeatureModel> list()定义方法
  {
  string sql = "SELECT id,feature_name FROM " + this.tablename + " ORDER BY id DESC";
  SqlDataReader sdr = getReader(sql, null);
  List<FeatureModel> flist = new List<FeatureModel>();
  if (sdr.HasRows)
  {
  while (sdr.Read())
  {
  FeatureModel mm = new FeatureModel();
  mm.id = Convert.ToInt32(sdr["id"].ToString());
  mm.feature_name = sdr["feature_name"].ToString();
  flist.Add(mm);
  }
  }
  sdr.Close();
  return flist;
  }

  public void delete(int id)定义方法
  {
  string sql = "DELETE FROM "+this.tablename+" WHERE id=@id";
  SqlParameter[] parArray = { 
  CommonLb.makeParam("@id",SqlDbType.Int,id)操作数据库
  };
  excuteQuery(sql, parArray);
  }

  public int add(string feature_name)
  {
  string sql = "INSERT INTO " + this.tablename + "(feature_name) VALUES(@feature_name)";
  SqlParameter[] parArray = { 
  CommonLb.makeParam("@feature_name",SqlDbType.NVarChar,feature_name)操作数据库
  };
  return excuteQuery(sql, parArray);
  }
  public FeatureModel getOne(int id)
  {
  if (id <= 0)
  return null;
  FeatureModel mm = new FeatureModel();
  SqlParameter[] parArray = { 
  CommonLb.makeParam("@id",SqlDbType.Int,id)
  };
  string sql = "SELECT TOP 1 id,feature_name FROM " + this.tablename + " WHERE id=@id";
  SqlDataReader sdr = getReader(sql, parArray);操作数据库
  if (sdr.HasRows)
  {
  sdr.Read();
  mm.feature_name = sdr["feature_name"].ToString();
  mm.id = Convert.ToInt32(sdr["id"].ToString());
  }
  sdr.Close();
  return mm;
  }

  public int update(int id, string feature_name)
  {
  string sql = "UPDATE " + this.tablename + " SET feature_name=@feature_name WHERE id=@id";
  SqlParameter[] parArray = { 
  CommonLb.makeParam("@feature_name",SqlDbType.NVarChar,feature_name),
  CommonLb.makeParam("@id",SqlDbType.Int,id)操作数据库
  };
  return excuteQuery(sql, parArray);
  }
  }
}

补充：.NET技术 ,  C#