When Display data in datagridview it take too much time although data not more why and how to reduce time

Problem

When Display data in datagridview it take too much time although data not more why and how to reduce time .

Data Display in datagridview windows form is 325 members only and not big data .

It take too much time when press buttonshow click event to show data in datagridview

it take may be 45 minutes meaning it take 3/4 hour to show data in datagridview 

why and how to reduce time

private void GetMemberAccount(string MemberCode)
    {
        Tax = GetTax();
        DataTable DTPriceList;
        Annual = 0; UnderAge = 0; OverAge = 0; BabySitter = 0;
        TotalUnderAge = 0; TotalOverAge = 0; TotalAnnual = 0; NetTotalAnnual = 0;
        CridtValue1 = 0; CridtValue2 = 0;



        string SQL = @"Select * From View_MembersWithPriceList where  (MemberCode = N'" + MemberCode + "') and (RelatedMemberCode  IS NULL) and (Member ='True')  AND (Year = " + txtYear.Text + ")";
        DTPriceList = DataAccess.ExecuteDataTable(SQL);

        if (DTPriceList.Rows.Count > 0)
        {
            if (!string.IsNullOrEmpty(Convert.ToString(DTPriceList.Rows[0]["Annual"])))
            {
                Annual = Convert.ToDouble(DTPriceList.Rows[0]["Annual"]);
            }

            if (!string.IsNullOrEmpty(Convert.ToString(DTPriceList.Rows[0]["KidsUnderAge"])))
            {
                UnderAge = Convert.ToDouble(DTPriceList.Rows[0]["KidsUnderAge"]);
            }

            if (!string.IsNullOrEmpty(Convert.ToString(DTPriceList.Rows[0]["OverAgeChildPrice"])))
            {
                OverAge = Convert.ToDouble(DTPriceList.Rows[0]["OverAgeChildPrice"]);
            }

            if (!string.IsNullOrEmpty(Convert.ToString(DTPriceList.Rows[0]["OverAgeChildPrice"])))
            {
                OverAge = Convert.ToDouble(DTPriceList.Rows[0]["OverAgeChildPrice"]);
            }

            if (!string.IsNullOrEmpty(Convert.ToString(DTPriceList.Rows[0]["BabySitter"])))
            {
                BabySitter = Convert.ToDouble(DTPriceList.Rows[0]["BabySitter"]);
            }
            if (!string.IsNullOrEmpty(Convert.ToString(DTPriceList.Rows[0]["ManagmentFees"])))
            {
                ManagmentFees = Convert.ToDouble(DTPriceList.Rows[0]["ManagmentFees"]);
            }
            if (!string.IsNullOrEmpty(Convert.ToString(DTPriceList.Rows[0]["CardFees"])))
            {
                CardFees = Convert.ToDouble(DTPriceList.Rows[0]["CardFees"]);
            }
            TotalUnderAge = ChildUndrAge(MemberCode);
            TotalOverAge = ChildOverAge(MemberCode);
            CountCard = GetCountCards(MemberCode);
            if(CountCard > 0)
            {
                TotalCardAmount = CountCard * CardFees;
            }

            if (TotalUnderAge > 0)
            {
                TotalUnderAge = TotalUnderAge * UnderAge;
            }

            if (TotalOverAge > 0)
            {
                TotalOverAge = TotalOverAge * OverAge;
            }


            if (BabySiter(MemberCode) == false)
            {
                BabySitter = 0;
            }

            TotalAnnual = (Annual + TotalUnderAge + TotalOverAge + BabySitter + ManagmentFees + TotalCardAmount);

            NetTotalAnnual = TotalAnnual;

            int Diff = DiffDate(MemberCode);

            if (Diff < 12 && Diff !=0)
            {
                double CustomAnnual = TotalAnnual / 12;
                TotalAnnual = Math.Round(CustomAnnual * Diff, 2);
            }

            if (Diff ==0)
            {
                TotalAnnual = 0;
            }


            if (TotalAnnual > 0)
            {
                TotalDue= CridtValue1 = Math.Round((TotalAnnual / Tax),2);
                TotalTax = TotalAnnual - TotalDue;
                CridtValue2 = Math.Round(TotalAnnual - CridtValue1, 2);
            }

        }
    }

Under button show this code is written

 if (!string.IsNullOrEmpty(txtYear.Text))
        {

           
            string Sql = "Select * From View_MembersWithPriceList where  (RelatedMemberCode  IS NULL) and (Member ='True') AND (Year = " + txtYear.Text + ")";
            DT = DataAccess.ExecuteDataTable(Sql);

            if (DT.Rows.Count > 0)
            {
                Grid.DataBinding(DT);

                for (int i = 0; i < Grid.Rows.Count; i++)
                {
                    MemberCode = Convert.ToString(Grid.Rows[i].Cells["MemberCode"].Value);

                    if (!string.IsNullOrEmpty(MemberCode))
                    {
                        GetMemberAccount(MemberCode);

                        Grid.Rows[i].Cells["AnnualValue"].Value = Annual;
                        Grid.Rows[i].Cells["OverAge"].Value = TotalOverAge;
                        Grid.Rows[i].Cells["UnderAge"].Value = TotalUnderAge;
                        Grid.Rows[i].Cells["BabySitter"].Value = BabySitter;
                        Grid.Rows[i].Cells["NetTotal"].Value = NetTotalAnnual;
                        Grid.Rows[i].Cells["TotalDue"].Value = TotalAnnual;
                        Grid.Rows[i].Cells["Total"].Value = TotalDue;
                        Grid.Rows[i].Cells["TotalTax"].Value = TotalTax;

                    }

                }
            }