Code for downloading large amount of data file >5MB

protected void Download(object sender, EventArgs e)

    {

        string filename = Convert.ToString(((LinkButton)sender).CommandArgument);

        string filepath = "../Content/Files/";

        filepath = filepath + "" + filename;

        string extension = System.IO.Path.GetExtension(filename).ToString();

        if (filename != "")

        {

            if (extension == ".doc" || extension == ".docx")

            {

                if (File.Exists(Server.MapPath(filepath)))

                {

                    if (extension == ".docx")

                    {

                        Response.ContentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document";

                    }

                    else

                    {

                        Response.ContentType = "application/msword";

                    }

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

                    Response.WriteFile(filepath);

                    Response.End();

                    Response.Flush();

                }

            }

            else

            {

                if (File.Exists(Server.MapPath(filepath)))

                {

                    Response.ClearContent();

                    Response.ClearHeaders();

                    Response.ContentType = "application/pdf";

                    Response.AddHeader("Content-Disposition", "attachment; filename=" +

                    filename);

                    Response.WriteFile(filepath);

                    Response.End();

                }

            }

        }

    }