ASP.Net ThreadAbortException: Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack

Hi ,

Please give me an idea why its executing catch block.

Error :

Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack

 Code Behind Code:

            try
            {
                string filePath = (sender as LinkButton).CommandArgument;
                Response.ContentType = ContentType;
                Response.AppendHeader("Content-Disposition", "attachment; filename=" + Path.GetFileName(filePath));
                Response.WriteFile(filePath);
                Response.End();
            }
            catch (ThreadAbortException lException)
            {
                // do nothing
            }
            catch (Exception ex)
            {
                throw ex;
            }

 Front End code in content place holder

                                    <asp:GridView BorderStyle="Outset" BorderColor="#ddd" BorderWidth="1px" ShowHeader="False" ID="GridViewShowFiles" runat="server" AutoGenerateColumns="False" EmptyDataText="No files uploaded"
                                        CellPadding="4" AlternatingRowStyle-BackColor="#dff0d8" RowStyle-BackColor="#dff0d8"
                                        RowStyle-Height="40px"
                                        GridLines="None" Width="100%">
                                        <Columns>
                                            <asp:BoundField DataField="Text" />
                                            <asp:TemplateField ControlStyle-CssClass="pull-right">
                                                <ItemTemplate>
                                                    <asp:LinkButton ID="lnkDownload" Text="Download" CommandArgument='<%# Eval("Value") %>' runat="server" OnClick="DownloadFile"></asp:LinkButton>

                                                </ItemTemplate>
                                            </asp:TemplateField>
                                            <asp:TemplateField>
                                                <ItemTemplate>
                                                    <asp:LinkButton CssClass=" pull-right" ID="lnkDelete" Text="" CommandArgument='<%# Eval("Value") %>'
                                                        runat="server" OnClick="DeleteFile">
                                                       <span title="Remove" class="glyphicon glyphicon-trash alert-danger pull-right" ></span>
                                                    </asp:LinkButton>
                                                </ItemTemplate>
                                            </asp:TemplateField>
                                        </Columns>
                                    </asp:GridView>

its executing threadabortexception .

I used same link as explained in the portal but as per my requirement i used in master page inside contentplaceholder i binded grid.