将SqlDataReader 数据集转化为datatbale ,在将datatable 转化为iList

public IList GetModelList(string tablename, string where)
         {           
             IList list = null;
             DataTable dataTable = new DataTable();
             string sql = "select * from " + tablename;
             if (where != "")
             {
                 sql += " Where " + where;
             }
             try
             {
                 System.Data.SqlClient.SqlDataReader dr = DbHelperSQL.ExcuteReader(sql);                 
                 for (int i = 0; i < dr.FieldCount; i++)
                 {
                     DataColumn mydc = new DataColumn();    //关键的一步
                     mydc.DataType = dr.GetFieldType(i);
                     mydc.ColumnName = dr.GetName(i);
                     dataTable.Columns.Add(mydc);          //关键的第二步
                 }
                 while (dr.Read())
                 {
                     DataRow mydr = dataTable.NewRow();     //关键的第三步
                     for (int i = 0; i < dr.FieldCount; i++)
                     {
                         mydr[i] = dr[i].ToString();
                     }
                     dataTable.Rows.Add(mydr);            //关键的第四步
                     mydr = null;
                 }
                 dr.Close();
                 list = dataTable as IList;
                 return (list);

             }
             catch (Exception ex)
             {
                 throw ex;
             }            
         }