访问类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.Sql;
using System.Data.SqlClient;
using Models;

namespace DAL
{
   public class NewsService
    {
        //创建一个通用类
        private EFDBHelper helper = new EFDBHelper(new HotelDBEntities());

        /// <summary>
        /// 发布新闻：添加
        /// </summary>
        /// <param name="news"></param>
        /// <returns></returns>
        //public int PublishNews(News news)
        //{
        //    //using (HotelDBEntities db = new HotelDBEntities())
        //    //{
        //    //    db.News.Add(news);
        //    //   return  db.SaveChanges();
        //    //}
        //    return helper.Add<News>(news);
        //}

            //[下面是使用存储过程]
        public int PublishNews(News news)
        {

            SqlParameter[] param = new SqlParameter[]
                {
                    new SqlParameter("@NewsTitle",news.NewsTitle),
                    new SqlParameter("@NewsContents",news.NewsContents),
                    new SqlParameter("@CategoryId",news.CategoryId),
                };
            using (HotelDBEntities db = new DAL.HotelDBEntities())
            {
                return db.Database.ExecuteSqlCommand("execute usp_AddNews @NewsTitle,@NewsContents,@CategoryId",param);
            }
        }


        //修改新闻
        public int ModifyNews(News news)
        {
            return helper.Modify<News>(news);
        }


        //删除新闻
        public int DeleteNews(int newsId)
        {
            News news = new News { NewsId = newsId };
            return helper.Delete<News>(news);
        }

            /// <summary>
            /// 查询指定前几条新闻
            /// </summary>
            /// <param name="count"></param>
            /// <returns></returns>
        public List<News> GetNews(int count)
        {
            List<News> list;
            using (HotelDBEntities db=new DAL.HotelDBEntities())
            {
                return (from n in db.News
                        orderby n.PublishTime descending
                        select n).Take(count).ToList();
             }
        }


        /// <summary>
        /// 根据新闻Id查询新闻详细
        /// </summary>
        /// <param name="newsId"></param>
        /// <returns></returns>
        public News GetNewsById(int newsId)
        {
            using (HotelDBEntities db = new DAL.HotelDBEntities())
            {
              return    (from n in db.News where n.NewsId == newsId select n).FirstOrDefault();
            }
        }


        /// <summary>
        /// 获取所有的新闻分类
        /// </summary>
        /// <returns></returns>
        public List<NewsCategory> GetAllCategory()
        {
            using (HotelDBEntities db = new DAL.HotelDBEntities())
            {
                return (from c in db.NewsCategory select c).ToList(); 
            }
        }

        /// <summary>
        /// 根据新闻分类ID查询分类名称
        /// </summary>
        /// <param name="categoryId"></param>
        /// <returns></returns>
        public string GetCategoryName(int categoryId)
        {
            using (HotelDBEntities db = new DAL.HotelDBEntities())
            {
                return (from c in db.NewsCategory where c.CategoryId == categoryId select c.CategoryName).FirstOrDefault();
            }
        }
    }
}