Download File from C# through Web Method via Ajax call?

Question

I have tried to download the file from the server through the webmethod but it has not work for me. my code as below

     [System.Web.Services.WebMethod()]
         


        

Answer 1

This is Ajax Call

             $(".Download").bind("click", function () 
             {
                var CommentId = $(this).attr("data-id");
                $.ajax({
                   type: "POST",
                   contentType: "application/json; charset=utf-8",
                   url: "TaskComment.aspx/DownloadDoc",
                   data: "{'id':'" + CommentId + "'}",
                   success: function (data) {


                   },
                   complete: function () {

                }
            });
        });

Code Behind C#

   [System.Web.Services.WebMethod]
   public static string DownloadDoc(string id)
   {
       string jsonStringList = "";
       try
       {
        int CommentId = Convert.ToInt32(id);
        TaskManagemtEntities contextDB = new TaskManagementEntities();
        var FileDetail = contextDB.tblFile.Where(x => x.CommentId == CommentId).FirstOrDefault();
        string fileName = FileDetail.FileName;
        System.IO.FileStream fs = null;
        string path = HostingEnvironment.ApplicationPhysicalPath + "/PostFiles/" + fileName;
        fs = System.IO.File.Open(path + fileName, System.IO.FileMode.Open);
        byte[] btFile = new byte[fs.Length];
        fs.Read(btFile, 0, Convert.ToInt32(fs.Length));
        fs.Close();
        HttpContext.Current.Response.AddHeader("Content-disposition", "attachment; filename=" + fileName);
        HttpContext.Current.Response.ContentType = "application/octet-stream";
        HttpContext.Current.Response.BinaryWrite(btFile);
        HttpContext.Current.Response.End();
        fs = null;
        //jsonStringList = new JavaScriptSerializer().Serialize(PendingTasks);
    }
    catch (Exception ex)
    {

    }
    return jsonStringList;
}