How to create CSV file from db and save it in MVC

var response = System.Web.HttpContext.Current.Response;
            response.BufferOutput = true;

            //clear response
            response.Clear();
            response.ClearHeaders();
            response.ContentEncoding = Encoding.Unicode;

            //For Csv Export give file name
            string filename = string.Format("{0}", DateTime.Now.ToString("g").Replace("/", "-").Replace(":", "_").Replace(" ", "-"));
            response.AddHeader("content-disposition", "attachment;filename=MailMergeLog-" + filename + ".CSV ");
            response.ContentType = "text/plain";
            response.Write(sb.ToString());
            response.End();