改进后的筛选函数

  private void queryIndent_Click(object sender, EventArgs e)
        {
            string GS = this.CompanySelect.Text;
            string DDBH = this.OrderNumber.Text.Trim();
            string KHBH = this.CustomerNumber.Text.Trim();
            string CPBH = this.GoodsNumber.Text;
            string State = this.state.Text;
            string GGTZD = this.ChangeDoc.Text;
            string JLY = this.Recorder.Text.Trim();
            string StringKDRQfrom = this.OrderDateFrom.Value.ToString();
            string StringKDRQto = this.OrderDateTo.Value.ToString();
            string StringJHRQfrom = this.DeliveryDateFrom.Value.ToString();
            string StringJHRQto = this.DeliveryDateTo.Value.ToString();
            bool nullflag = true;

            if (DDBH != "")
            {
                DDBH = "DDBH like '%" + DDBH + "%'";
                nullflag = false;
            }
          

            if (GS != "")
                if (!nullflag)
                    GS = "and Company ='" + GS + "'";
                else
                {
                    GS = "Company ='" + GS + "'";
                    nullflag = false;
                }


            if (KHBH != "")
                if (!nullflag)
                    KHBH = "and KHBH like '%" + KHBH + "%'";
                else
                {
                    KHBH = "KHBH like '%" + KHBH + "%'";
                    nullflag = false;
                }

            if (CPBH != "")
                if (!nullflag)
                    CPBH = "and CX like '%" + CPBH + "%'";
                else
                {
                    CPBH = "CX like '%" + CPBH + "%'";
                    nullflag = false;
                }

            if (State != "")
                if (!nullflag)
                    State = "and State like '%" + State + "%'";
                else
                {
                    State = "State like '%" + State + "%'";
                    nullflag = false;
                }

            if (GGTZD != "")
                if (!nullflag)
                    GGTZD = "and GGD like '%" + GGTZD + "%'";
                else
                {
                    GGTZD = "GGD like '%" + GGTZD + "%'";
                    nullflag = false;
                }

            if (JLY != "")
                if (!nullflag)
                    JLY = "and ZDY like '%" + JLY + "%'";
                else
                {
                    JLY = "ZDY like '%" + JLY + "%'";
                    nullflag = false;
                }

           if (StringKDRQfrom!="")
               if (!nullflag)
                   StringKDRQfrom = "and ZDRQ >'" + StringKDRQfrom + "'";
               else
               {
                   StringKDRQfrom = "ZDRQ >'" + StringKDRQfrom + "'";
                   nullflag = false;
               }

          if (StringKDRQto!="")
              if (!nullflag)
                  StringKDRQto = "and ZDRQ < '" + StringKDRQto + "'";
              else
              {
                  StringKDRQto = "ZDRQ < '" + StringKDRQto + "'";
                  nullflag = false;
              }


            if (StringJHRQfrom!="")
                if (!nullflag)
                    StringJHRQfrom = "and CHRQ > '" + StringJHRQto + "'";
                else
                {
                    StringJHRQfrom = "CHRQ > '" + StringJHRQfrom + "'";
                    nullflag = false;
                }


          if (StringJHRQto!="")
              if (!nullflag)
                  StringJHRQto = "and CHRQ < '" + StringJHRQto + "'";
              else
              {
                  StringJHRQto = "CHRQ < '" + StringJHRQto + "'";
                  nullflag = false;
              }


            string sql = "select DDBH,Company,ZDRQ,KHBH,DHDW,CX,SL,CHRQ,State,SM,ZDY,GGD from DHZZD where " + DDBH + GS + KHBH + CPBH + State + GGTZD + JLY + StringKDRQfrom + StringKDRQto + StringJHRQfrom + StringJHRQto;
 
            BindSearchResult(sql);

            SetColumns();
        }

    }
}