关于条件查询的参数condition的最佳方案

        当我们在DAL层写一个方法进行对数据的条件查询时：

                   public IList<UserInfo> GetUsersByCondition( stiring condition )

                      {

                           string   strSql=string.Format(" select * from UserInfo where {0}" ,conditon);

                           return GetUsreInfoBySql( strSql );

                      }

         时须在界面层对condition有二种处理：

          1.使用System.Text.StringBuilder处理，这种处理方式对于条件很多的情况有助于代码效率和内存使用。下面是查询按钮下的代码：

              protected  void  btnSearch_Click( object sender,EventArgs e )

               {

                  System.Text.StringBuilder  sb=new  System.Text.StringBuilder();

                  sb.Append("  1=1  ");

                  if ( ddlBranchThree.SelectedValue != "-1")

                     {

                        sb.AppendFormat("  and  Ctk_no={0}", ddlBranchThree.SelectedValue);

                     }

                  if ( ddlBranchTwo.SelectedValue != "-1")

                   {

                      sb.AppendFormat( "   and Cn_no={0}",ddlBranchTwo.SelectedValue);

                   }

                  if ( TxtTimeFirst.Value!=""&& TxtTimeEnd.Value!="")

                   {

                     sb.AppandFormat("  and Create_Time  between  '{0}'  and  '{1}'  ",TxtTimeFirst.Value+"0:00:00",TxtTimeEnd.Value+"23:59:59");

                   }

                  string   condition = sb.ToString();

                   Session["condition"] = condition  ;    //传向另一个页 面

                         ......

               }

           第二种   以string 累加的方式，这里略！