ASP.net GridView AllowSorting does not create hyperlinks in the headings

Question

I would like to implement custom sorting on a custom databound GridView. OnSorting has been implemented and I already know that I need to modify that to make the sort work. Unfortuantely for some reason when I run the page it doesn't create the hyperlinks on the headings to be clicked to trigger the event:

<asp:GridView ID="dgEnrollmentTracker" runat="server" AllowPaging="True" OnSorting="dgEnrollmentTracker_Sorting"
    AllowSorting="True" AutoGenerateColumns="False" EnableModelValidation="True"
    Font-Size="8.5pt" Width="1930px" Font-Names="verdana,tahoma,sans-serif">
    <Columns>
        <asp:HyperLinkField DataNavigateUrlFields="Name URL" DataTextField="Name" 
            HeaderText="Name" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="75px" HorizontalAlign="Left" />
        </asp:HyperLinkField>

        <asp:BoundField DataField="Site ID" HeaderText="Site ID" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="75px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="S Date" HeaderText="S Date" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="125px" HorizontalAlign="Left" />
        </asp:BoundField>


        <asp:BoundField DataField="P Initials" HeaderText="P Initials" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="125px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="PID" HeaderText="PID" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="75px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="Type" HeaderText="Type" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="125px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="Eligibility" HeaderText="Eligibility" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="75px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="Ent Date Mailed" HeaderText="Ent Date Mailed" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="125px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="PReached" HeaderText="PReached" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="125px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="Ento Date Mailed" HeaderText="Ento Date Mailed" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="125px" HorizontalAlign="Left" />
        </asp:BoundField>


        <asp:BoundField DataField="EDate" HeaderText="EDate" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="125px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="DoS" HeaderText="DoS" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="125px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="BSC" HeaderText="BCS" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="75px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="SC" HeaderText="SC" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="75px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="Modified" HeaderText="Modified" >
        <HeaderStyle HorizontalAlign="Left" Font-Bold="False" />
        <ItemStyle Width="165px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="Modified By" HeaderText="Modified By" >
        <HeaderStyle HorizontalAlign="Left" />
        <ItemStyle Width="225px" HorizontalAlign="Left" />
        </asp:BoundField>

        <asp:BoundField DataField="Created" HeaderText="Created" >
        <HeaderStyle HorizontalAlign="Left" />
        <ItemStyle Width="165px" HorizontalAlign="Left" />
        </asp:BoundField>

    </Columns>
    <PagerStyle BorderStyle="None" HorizontalAlign="Center" 
        VerticalAlign="Middle" />
</asp:GridView>

Answer 1

Check This out sortexpression property

  `<asp:BoundField DataField="PReached" HeaderText="PReached"
        SortExpression="PReached" ReadOnly="True" />`