Kendo UI Upload not returning onSuccess

Question

Kendo UI Upload does not seem to return onSuccess even though the file gets uploaded. Below is the code I am using in C# on page load. I need to file name to be returned

What am I doing wrong here?

public string ProcessRequest()
{

        Response.Expires = -1;
        try
        {

            HttpPostedFile postedFile = Request.Files["files"];
            string savepath = Server.MapPath(System.Configuration.ConfigurationManager.AppSettings["ExcelImport"]);
            string filename = CL.GenerateUniqueName(postedFile.FileName, Session["LoginUserID"].ToString());  \\ <== generate a unique file name and return it to upload
            if (!Directory.Exists(savepath))
                Directory.CreateDirectory(savepath);
            string strCompath = Path.Combine(savepath, filename);
            postedFile.SaveAs(strCompath);
            Response.ContentType = "text/plain";
            string json = JsonConvert.SerializeObject(filename, Formatting.Indented); //<== tried to convert to json but still does not work
            return "";
        }
        catch (Exception ex)
        {
            Response.Write(ex.ToString());
            return ex.ToString();
        }
 }

Javascript of success code

function onSuccess(e) {
                console.log("Success (" + e.operation + ") :: " + getFileInfo(e));
}

Edit 1

I found that entire html seems to be rendered after uploading. How do I just return the uniquefilename?

Update

What I did to resolve this issue was call another aspx file that had no html and got the correct response. Not sure if this is the correct way but works for me. Now just need to find out how to get the unique file name back.

My Code:

$("#files").kendoUpload({
   async: {
           saveUrl: "Response.aspx",  //<== earlier this was pointing to the current aspx where the control is
           removeUrl: "remove",
           autoUpload: true
          },
             showFileList: true,
             success: onSuccess,
             remove: onRemove,
             upload: onUpload,
             complete: onComplete,
             error: onerror
   });

Server Code:

 protected void Page_Load(object sender, EventArgs e)
 {

           Response.Expires = -1;
            try
            {

                HttpPostedFile postedFile = Request.Files["files"];
                string savepath = Server.MapPath(System.Configuration.ConfigurationManager.AppSettings["ExcelImport"]);
                string filename = CL.GenerateUniqueName(postedFile.FileName, Session["LoginUserID"].ToString());
                if (!Directory.Exists(savepath))
                    Directory.CreateDirectory(savepath);
                string strCompath = Path.Combine(savepath, filename);
                postedFile.SaveAs(strCompath);
                Context.Response.Clear();
                Context.Response.ContentType = "text/plain";
                Context.Response.Write("{}");

            }
            catch (Exception ex)
            {
                Response.Write(ex.ToString());
                // return ex.ToString();
            }

    }

Answer 1

For future reference,

You should be using a WebService (ASMX) file to process and return your JSON. Remember that the javascript success block will only be called with a returned http 200 status code.

If you ever get to using the MVC framework its even easier by just returning a JSON result type.

If you wanted to keep the aspx hack, you can call the following to remove the HTML

response.clear();
response.write(yourJSON);
response.end();

But again i would discourage from doing this and recommend the dedicated service.