添加新闻在分层里的实现

刚开懂一个添加新闻的流程：

在表现层中，用下面一句代码条用bll中的方法
 sc.BLL.News bll = new sc.BLL.News();

 protected void btnSubmit_Click(object sender, EventArgs e)
    {
          if(r>0)
        {
            Page.ClientScript.RegisterStartupScript(this.GetType(), "s", "<script>alert('新闻添加成功！');location.reload('AddNews.aspx')</script>");
        }
    }

bll中：private readonly sc.IDAL.INews dal = DataAccess.CreateNews();

        public int Add(sc.Model.News model)
        {
            return dal.Add(model);
        }

IDAL中： 

 int Add(sc.Model.News model);

DAL中

 public class News : INews
{

   public int Add(sc.Model.News model)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("insert into [News](");
            strSql.Append("[Title],[Author],[NewsFrom],[NCID],[NewsType],[NewsContent])");
            strSql.Append(" values (");
            strSql.Append("@Title,@Author,@NewsFrom,@NCID,@NewsType,@NewsContent)");
            strSql.Append(";select @@Identity");
            SqlParameter[] parameters = {
                    new SqlParameter("@Title", SqlDbType.VarChar,50),
                    new SqlParameter("@Author", SqlDbType.NVarChar,15),
                    new SqlParameter("@NewsFrom", SqlDbType.NVarChar,100),
                    new SqlParameter("@NCID", SqlDbType.Int),
                    new SqlParameter("@NewsType", SqlDbType.Int),
                    new SqlParameter("@NewsContent", SqlDbType.Text)
            };
            parameters[0].Value = model.Title;

            if (model.Author != null)
                parameters[1].Value = model.Author;
            else
                parameters[1].Value = DBNull.Value;


            if (model.NewsFrom != null)
                parameters[2].Value = model.NewsFrom;
            else
                parameters[2].Value = DBNull.Value;

            parameters[3].Value = model.NCID;
            parameters[4].Value = model.NewsType;
            parameters[5].Value = model.NewsContent;
            return SqlHelper.GetInt(SqlHelper.GetSingle(SqlHelper.LocalSqlServer, strSql.ToString(), parameters));
        }

}