建模时候多写个Author或UserName的属性,BLL里连接表把值取出来就ok了。demo写得粗糙，见笑

Model:

public class News
    {
        public News()
  {}

  private int _id;

private int _uid;
  private int _category1;
  private int _category2;
  private int _category3;
  private string _title;
  private string _author;
  private string _source;


  private string _content;
  

  public int NewsId
  {
   set{ _id=value;}
   get{return _id;}
  }

  public int UserId
  {
   set{ _uid=value;}
   get{return _uid;}
  }
  /// <summary>
  ///
  /// </summary>
  public int Category1
  {
   set{ _category1=value;}
   get{return _category1;}
  }
  /// <summary>
  ///
  /// </summary>
  public int Category2
  {
   set{ _category2=value;}
   get{return _category2;}
  }
  /// <summary>
  ///
  /// </summary>
  public int Category3
  {
   set{ _category3=value;}
   get{return _category3;}
  }

  /// <summary>
  ///
  /// </summary>
  public string Title
  {
   set{ _title=value;}
   get{return _title;}
  }
  /// <summary>
  ///
  /// </summary>
  public string Author
  {
   set{ _author=value;}
   get{return _author;}
  }
  /// <summary>
  ///
  /// </summary>
  public string Source
  {
   set{ _source=value;}
   get{return _source;}
  }

public string Content
  {
   set{ _content=value;}
   get{return _content;}
  }

BLL:

        /// <summary>
        /// 得到一个对象实体
        /// </summary>
        public Model.News GetModel(int id)
        {
            StringBuilder strSql = new StringBuilder();
            strSql.Append("select News.*,Users.UserName from News ");
strSql.Append("LEFT JOIN Users ON Users.UserId=News.UserId");
            strSql.Append(" where NewsId=" + id);
            Model.News model = new Model.News();
            DataTable dt = SQLHelper.PopulateDataTable(strSql.ToString());
            model.NewsId = id;
            if (dt.Rows.Count > 0)
            {
if (dt.Rows[0]["UserId"].ToString() != "")
                {
                    model.UserId = int.Parse(dt.Rows[0]["UserId"].ToString());
                }
                if (dt.Rows[0]["Category1"].ToString() != "")
                {
                    model.Category1 = int.Parse(dt.Rows[0]["Category1"].ToString());
                }
                if (dt.Rows[0]["Category2"].ToString() != "")
                {
                    model.Category2 = int.Parse(dt.Rows[0]["Category2"].ToString());
                }
                if (dt.Rows[0]["Category3"].ToString() != "")
                {
                    model.Category3 = int.Parse(dt.Rows[0]["Category3"].ToString());
                }
                model.Title = dt.Rows[0]["Title"].ToString();
                model.Author = dt.Rows[0]["UserName"].ToString();
                model.Source = dt.Rows[0]["Source"].ToString();
                model.NewsPic = dt.Rows[0]["NewsPic"].ToString();
                model.ExUrl = dt.Rows[0]["ExUrl"].ToString();
                model.Content = dt.Rows[0]["Content"].ToString();
                return model;
            }
            else
            {
                return null;
            }
        }