How to zip and unzip file using C#.net and Asp.net with third party ionic.zip.dll

// Extract files from Zip file
        protected void btnExtract_Click(object sender, EventArgs e)
        {
            if (fuBrowse.HasFile)
            {
                string uploadedFile = Path.GetFileName(fuBrowse.PostedFile.FileName);
                string location = Server.MapPath("~/ZipFiles/" + uploadedFile);
                fuBrowse.SaveAs(location);
                ZipFile fileToExtract = ZipFile.Read(location);
                fileToExtract.Password = "";
                fileToExtract.ExtractAll(Server.MapPath("~/extracted_file"), ExtractExistingFileAction.DoNotOverwrite);
                gridviewExtractedFiles.DataSource = fileToExtract.Entries;
                gridviewExtractedFiles.DataBind();
                lblMessage.Text = "Archive extracted successfully and containes following files";
            }
            else
            {
                lblMessage.Text = "No File Choosen";
            }
        }

//Making a file to password protected zip where password is chosen from a text box.

protected void btnZip_Click(object sender, EventArgs e)
       {
           if (fuBrowse.HasFile)
           {
               Response.ContentType = "application/zip";
               Response.AddHeader("content-disposition",
                "attachment;filename=a.zip");
               Response.Cache.SetCacheability(HttpCacheability.NoCache);
               string fileName = Path.GetFileName(fuBrowse.PostedFile.FileName);
               string fileLocation = Server.MapPath("~/zip_uploadedfile/" + fileName);
               fuBrowse.SaveAs(fileLocation);
               ZipFile createZipFile = new ZipFile();
               if (txtPassword.Text == string.Empty)
               {
                   lblMessage.Text = "Please put the password";
               }
               createZipFile.Password = txtPassword.Text.ToString();
               createZipFile.Encryption = EncryptionAlgorithm.PkzipWeak;
               createZipFile.AddFile(fileLocation, string.Empty);
               createZipFile.Save(Server.MapPath("~/zip_zipfile/a.zip"));
               gridviewExtractedFiles.DataSource = createZipFile.Entries;
               gridviewExtractedFiles.DataBind();
               lblMessage.Text = "Zip sucessfully created";
               Response.TransmitFile("~/zip_zipfile/a.zip");
               Response.End();

           }
           else
           {
               lblMessage.Text = "No File Choseen";
           }
       }