sorting in gridview using objectdatasource, start row index reverts to 0

See more:

C#

Hi
Can anybody help me. I have a grid view which uses object data source. I have pagination. Let me say that I am on page 3. The start row index reverts to 0 every time I hit one of the sort column links. This points me to page 1 instead of remaining on page 3. Could someone help me.

<asp:GridView ID="gvCategory" runat="server" AutoGenerateColumns="False" AllowPaging="True" DataSourceID="objDs"
                            EnableSortingAndPagingCallbacks="True" ShowFooter="True" AllowSorting="True"
                            OnRowCommand="gvCategory_RowCommand" Width="100%" OnRowDataBound="gvCategory_RowDataBound" >
                            <Columns>
                                <asp:TemplateField HeaderText="#" HeaderStyle-Width="2%" HeaderStyle-HorizontalAlign="Left"
                                    HeaderStyle-Font-Underline="false">
                                    <ItemTemplate>
                                        <%# (((GridView)((GridViewRow)Container).Parent.Parent).PageIndex) * ((GridView)((GridViewRow)Container).Parent.Parent).PageSize + Container.DataItemIndex + 1 %>
                                        <asp:HiddenField ID="hdfID" runat="server" Value='<%# Eval("ID") %>' />
                                    </ItemTemplate>
                                    <HeaderStyle Font-Underline="False" HorizontalAlign="Left" Width="2%" />
                                </asp:TemplateField>
                                <asp:BoundField DataField="CategoryName" HeaderText="Category Name" SortExpression="CategoryName" />
                                <asp:BoundField DataField="CategoryDescription" HeaderText="Category Description"
                                    SortExpression="CategoryDescription" />
                                <asp:BoundField DataField="StatusDesc" HeaderText="Status" SortExpression="StatusDesc" />
                                <asp:TemplateField HeaderStyle-Font-Underline="false" HeaderStyle-Width="5%" ShowHeader="False">
                                    <ItemTemplate>
                                        <asp:LinkButton ID="lnkGvSelect" runat="server" CausesValidation="False" CommandArgument='<%# Eval("ID") %>'
                                            CommandName="Select"  />
                                    </ItemTemplate>
                                    <HeaderStyle Font-Underline="False" Width="5%" />
                                </asp:TemplateField>
                            </Columns>
                            <EmptyDataTemplate>
                                <asp:Label ID="lblNoAvailableData" runat="server" SkinID="GridViewNoDataAvailable"
                                    Text="No Record Found"></asp:Label>
                            </EmptyDataTemplate>
                        </asp:GridView>



<asp:ObjectDataSource ID="objDs" TypeName="IFBS.Web.Course.Maint.UI.GridViewListingClass" SelectMethod="BindGrid" runat="server" 
        SelectCountMethod="GetGridRowCount" EnablePaging="true" StartRowIndexParameterName="StartRow" MaximumRowsParameterName="PageSize" SortParameterName="SortBy" >
        <SelectParameters>
            <asp:ControlParameter Name="srchTxt"  ControlID="txtSearch" PropertyName="Text" />
            <asp:ControlParameter Name="pgIdx"  ControlID="gvCategory" PropertyName="PageIndex" />
            
        </SelectParameters>

Thanks in advance
prasharvi