MVC-表单上传异常处理

Question

I have a controller method which returns response to download. It is working fine but when there is an exception occurs a blank page returned on the current page, where download is requested.

Also I am sending some form data to request the download.

Instead I need to show the error message as popup. How could I do that?

MVC Controller Method to download pdf. Its return pdf to download but sometimes when exception occurs it return a blank page.

  [HttpPost]
  public void Downloadpdf()
  {
      try
      {
        // Generate pdf
            Response.Clear();
            Response.AddHeader("Content-Type", "application/pdf");
            Response.AddHeader("Content-Disposition", "attachment;filename=Newpdf.pdf");
            byte[] pdf = ms.ToArray();
            Response.OutputStream.Write(pdf, 0, pdf.Length);
            Response.End();

       }
       catch (Exception ex)
       {
           Response.End();
       }
   }  

How should I show popup for the exception. And avoid blank page. Also it is a Single Page Application.

Answer 1

1) Remove void and use ActionResult

2) Use "return View("YourViewName");" after catch statement

3) In catch, add a line: ViewBag.Exception = ex;

4) On the view where you return, type

@if(ViewBag.Exception == null)
{
}
else
{
@ViewBag.Exception
}

5) You want to show on popup, use alert on the same view using javascript.

Hope the points satisfy your problem.

Answer 2

in you main page,put a iframe 0 width 0 height
when click download button ,set the iframe src to you download action
if everything is ok,return File(...)
if has some error ,return View(...)
and the view show in iframe,you can use some js to control the main page in iframe page to popup

main page

function pop(){....}  

iframe page

$(function(){ window.parent.pop(); });