gridview result blank when sort is done.

[96silvia]

I have a data grid that I want to sort and page the results.
but when I click on the title to sort or page it returns a blank page. I am using visual studio 2010 C#
here is my aspx code

     <asp:GridView ID="GridView1"  runat="server" 
                AutoGenerateColumns="False" PageSize="20"
                AllowSorting="True" OnSorting="GridView1_Sorting"
                AllowPaging="True" OnPageIndexChanging="GridView1_PageIndexChanging"
                style="margin-left: 0px" width="400px" CellPadding="1
                " ForeColor="#333333" 
                GridLines="None">
                <AlternatingRowStyle BackColor="White" />
                <Columns>
 
 
                   <asp:hyperlinkfield headertext="ImageID"
                   DataTextField="ImageID"
                   DataNavigateUrlFields="ImageID"
                   NavigateUrl ="C:\"
 
 
                   DataNavigateUrlFormatString="./ImageID.jpg" />
 
 
                    <asp:BoundField DataField="GivenName" HeaderText="GivenName" 
                        SortExpression="GivenName" />
                    <asp:BoundField DataField="Surname" HeaderText="Surname" 
                        SortExpression="Surname" />
                    <asp:BoundField DataField="DeathYear" HeaderText="DeathYear" 
                        SortExpression="DeathYear" />
                    <asp:BoundField DataField="BirthYear" HeaderText="BirthYear" 
                        SortExpression="BirthYear" />
                    <asp:BoundField DataField="FatherGivenNm" HeaderText="FatherGivenNm" 
                        SortExpression="FatherGivenNm" />
                    <asp:BoundField DataField="FatherSurname" HeaderText="FatherSurname" 
                        SortExpression="FatherSurname" />
                    <asp:BoundField DataField="MotherSurname" HeaderText="MotherSurname" 
                        SortExpression="MotherSurname" />
                    <asp:BoundField DataField="MotherGivenNm" HeaderText="MotherGivenNm" 
                        SortExpression="MotherGivenNm" />
                    <asp:BoundField DataField="SpouseGivenNm" HeaderText="SpouseGivenNm" 
                        SortExpression="SpouseGivenNm" />
                    <asp:BoundField DataField="SpouseSurname" HeaderText="SpouseSurname" 
                        SortExpression="SpouseSurname" />
                </Columns>
                <EditRowStyle BackColor="#2461BF" />
                <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
                <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                <RowStyle BackColor="#EFF3FB" />
                <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
                <SortedAscendingCellStyle BackColor="#F5F7FB" />
                <SortedAscendingHeaderStyle BackColor="#6D95E1" />
                <SortedDescendingCellStyle BackColor="#E9EBEF" />
                <SortedDescendingHeaderStyle BackColor="#4870BE" />
            </asp:GridView>
 
 
my code behind
 
 
 
        public void bindGridView(string sortExp, string sortDir)
 
            {
            if (GridView1.Rows.Count >0 )
                {
 
                System.Web.HttpContext context = System.Web.HttpContext.Current;
                fname = context.Session["fname"].ToString();
                lname = context.Session["lname"].ToString();
                birthMonth = context.Session["birthMonth"].ToString();
                birthDay = context.Session["birthDay"].ToString();
                birthYear = context.Session["birthYear"].ToString();
                deathMonth = context.Session["deathMonth"].ToString();
                deathDay = context.Session["deathDay"].ToString();
                deathYear = context.Session["deathYear"].ToString();
                fatherFname = context.Session["fatherFname"].ToString();
                fatherLname = context.Session["fatherLname"].ToString();
                motherFname = context.Session["motherFname"].ToString();
                motherLname = context.Session["motherLname"].ToString();
                spouseFname = context.Session["spouseFname"].ToString();
                spouseLname = context.Session["spouseLname"].ToString();
                ViewState["SortExpression"] = sortExp;
 
                dataTableResult = archiveAccess.GetDeathInfo(fname, lname, birthYear, deathYear, fatherFname, fatherLname, motherFname, motherFname, spouseFname, spouseLname);
 
                DataView myDataView = new DataView(dataTableResult);
 
                if ((GridView1 != null))
                    {
                    myDataView.Sort = string.Format("{0} {1}", sortExp, sortDir);
                    }
                    GridView1.DataSource = myDataView;
                    GridView1.AllowSorting = true;
                    GridView1.AllowPaging = true;
                    GridView1.DataBind();                
                }
            }
 
        protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
            {
 
            bindGridView(e.SortExpression, sortOrder);
 
            }