两种添加数据到WEB DropDownList 控件的方法

方法一：
     string sql="SELECT * FROM NewsClass ORDER BY ORDERID DESC";
     OleDbConnection conn=new OleDbConnection();
     conn.ConnectionString=ConnectionString;
     conn.Open();
     OleDbCommand cmd = new OleDbCommand(Sql,Conn);
     OleDbDataReader dr= cmd.ExecuteReader();
     //将数据添加到 DropDownList
     while(dr.Read())
     {
      this.ddlClass.Items.Add(new ListItem(dr["ClassName"].ToString(),dr["ClassId"].ToString()));
     }
     dr.Close();
     cmd.Dispose();
     conn.Close;
     conn.Dispose();
方法二：
  string sql="SELECT * FROM NewsClass ORDER BY ORDERID DESC";
     OleDbConnection conn=new OleDbConnection();
     conn.ConnectionString=ConnectionString;
     conn.Open();
 
     DataSet ds=new DataSet();
     OleDbDataAdapter da=new OleDbDataAdapter(sql,conn); 
     da.Fill(ds,"ClassTable");
     //将数据添加到 DropDownList
     this.ddlClass.DataSource=ds;
     this.ddlClass.DataTextField = "ClassName";
     this.ddlClass.DataValueField = "ClassID";
     this.ddlClass.DataBind();
     ds.Dispose();
     conn.Close;
     conn.Dispose();