Page Refresh in ASP.NET

Question

save dialog saves file to the local machine. But after that, my page stand there and do nothing for the rest of my process. I use below code to open a save dialog

protected void lnkbtnDownload_Click(object sender, EventArgs e)
{
  string fileName = startupPath + "bin\\Inbox.mdb";
  System.IO.FileInfo targetFile = new System.IO.FileInfo(fileName);

  if (targetFile.Exists)
  {
      Response.Clear();
      Response.AddHeader("Content-Disposition", "attachment; filename=" + targetFile.Name);
      Response.AddHeader("Content-Length", targetFile.Length.ToString());
      Response.ContentType = "application/octet-stream";
      Response.WriteFile(targetFile.FullName);                        
      Response.End();
  }
}

the html code is :

<asp:Button id="lnkbtnDownload" runat="server" CausesValidation="false" 
  Text="Download" CssClass="buttonstyle"  OnClick="lnkbtnDownload_Click"></asp:Button>

but after the file is save to local machine and the save dialog is close, my page no response at all. May I know how to do a postback to the page after the save dialog is close.?

score 9 · Accepted Answer · answered Apr 22 '09 at 11:14

9

Because you are calling Response.End, this halts the response of the page.

answered Apr 22 '09 at 11:14

Andrew Corkery

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Yes. But because the content type of the response has been changed from "text/html" to "application/octet-stream" there will be no output rendered in the browser. I would also suggest using a handler to serve out the file - e.g. you could pass a Guid on the query string to identify the desired file. – Andrew Corkery Apr 22 '09 at 12:47

score 5 · Answer 2 · answered May 23 '09 at 23:45

5

Put this code within an HttpHandler and then link to that handler from the original page, passing in whatever information your handler needs.

answered May 23 '09 at 23:45

Haacked

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Gosh, there's an awful lot of wrangling that seems to occur around this issue. The simple HttpHandler solution seems to be the straightforward and proper way to solve this. – Paul Prewett Aug 11 '09 at 12:51

score 4 · Answer 3 · answered Apr 22 '09 at 11:10

4

I think you should open a popup page / handler that does this Response.WriteFile operation.

answered Apr 22 '09 at 11:10

Canavar

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target="_blank" <- You can add this to your LinkButton (even though visual studio will give you squigglies – Martin Murphy May 27 '09 at 04:56

score 1 · Answer 4 · edited May 23 '17 at 12:13

Mark Brackett's answer to a similar question should work here, except you don't need the cross-page postback url attribute:

<script type="text/javascript">
   var oldTarget, oldAction;
   function newWindowClick(target) {
      var form = document.forms[0];
      oldTarget = form.target;
      oldAction = form.action;
      form.target = target;

      window.setTimeout(
         "document.forms[0].target=oldTarget;"
         + "document.forms[0].action=oldAction;", 
         200
      );
   }
</script>

<asp:LinkButton runat="server" id="lnkbtnDownload"
  CausesValidation="false" Text="Download" CssClass="buttonstyle" 
  OnClick="lnkbtnDownload_Click"
  OnClientClick="newWindowClick('download');" />

This will cause the postback to occur in a new window, and your existing Response handling will take care of the download. The original window form is restored for future interaction/postbacks.

score 0 · Answer 5 · answered Apr 22 '09 at 11:13

I'd say you can run this code inside an iframe or you can open a popup for triggering the file download. In this case you are overwriting the Response and the page you was expected to get loaded is lost.

So, I would move this code into a dedicated page and implement one of the two solutions mentioned above.

score 0 · Answer 6 · edited May 23 '17 at 12:19

0

You cannot answer a single request (i.e. button postback) with 2 responses.

You can however change the postback to redirect to a separate download/confirmation page, which in turn initiates the download using an iframe.

See this question

edited May 23 '17 at 12:19

Community

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answered May 23 '09 at 08:14

devio

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Page Refresh in ASP.NET

6 Answers6