Download DataList checkbox checked file in zip using Ionic.zip dll in asp.net

//////////////////// HTML

 using Ionic.Zip; namespace

<asp:DataList ID="DL_FileManagement" runat="server" DataKeyField="FileNames" RepeatDirection="Horizontal" RepeatLayout="Flow" CssClass="row col-lg-12"

CellPadding="2" CellSpacing="5">

   <ItemStyle ForeColor="Black" />

         <ItemTemplate>

           <div class="col-lg-2 p-0">

               <asp:CheckBox runat="server" ID="Chk_TabtoDownload" Style="float: left; margin-top: 6px; margin-right: -8px;" CssClass="pull-right" Text="&nbsp;" />

                  </div>

                       </ItemTemplate>

    </asp:DataList>

button

<asp:LinkButton runat="server" ID="lbtn_FMDataBulk" OnClick="lbtn_FMDataBulk_OnClick">

                                                     <i class="glyphicon glyphicon-download btn-success" style="font-size:15px; padding:5px;"></i>

                                                                </asp:LinkButton>

//////////////////////////////.cs

protected void Download_Files_Zip(List<string> filenames, string FolderName)

    {

        try

        {

            string fullPath = ResolveUrl("~/" + FolderName + "/");

            string chkFile = Server.MapPath("~/" + FolderName + "/");

            using (ZipFile zip = new ZipFile())

            {

                zip.AlternateEncodingUsage = ZipOption.AsNecessary;

                zip.AddDirectoryByName("Files");

                for (int i = 0; i < filenames.Count; i++)

                {

                    string Fpaths = chkFile + Convert.ToString(filenames[i]);

                    FileInfo fi = new FileInfo(Fpaths);

                    if (fi.Exists)

                    {

                        string filePath = fullPath + Convert.ToString(filenames[i]);

                        zip.AddFile(filePath, "Files");

                    }

                }

                Response.Clear();

                Response.BufferOutput = false;

                string zipName = String.Format("Zip_{0}.zip", DateTime.Now.ToString("yyyyMMMddHHmmss"));

                Response.ContentType = "application/zip";

                Response.AddHeader("content-disposition", "attachment; filename=" + zipName);

                zip.Save(Response.OutputStream);

                Response.End();

            }

        }

        catch (Exception)

        {

        }

    }

    protected void lbtn_FMDataBulk_OnClick(object sender, EventArgs e)

    {

        try

        {

            int i = 0;

            string[] files = new string[] { };

            List<string> filesNames = new List<string>();

            foreach (DataListItem item in DL_FileManagement.Items)

            {

                if ((item.FindControl("Chk_TabtoDownload") as CheckBox).Checked)

                {

                    filesNames.Add((item.FindControl("lbl_FilesNames") as Label).Text);

                    i++;

                }

            }

            Download_Files_Zip(filesNames, "Document");

        }

        catch (Exception)

        {

        }

    }