Member Avatar for shailaja mohite

Hi
I was created one web application. In which i am using the ajax control asyncfileupload file uploader in update panel.
Upload file correctly but when i refresh the page then double this file is uploaded..
how to fix this problem in asp.net? please help me
how to postback the page..

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  • Latest Post Latest Post by crishlay

Dani AI

Generated

Two likely causes — and simple fixes — for the behavior you describe (file uploads twice after a refresh):

  • Either the browser is re‑submitting a POST when the page is refreshed (the classic double-submit problem), or the AsyncFileUpload flow is actually performing two uploads: the control’s async upload, then your page code (or a forced postback such as a client __doPostBack) is re‑running the same save logic. and were right to suggest guarding Page_Load when you put save logic there, but when you use AjaxControlToolkit’s AsyncFileUpload the reliable place to persist the file is the control’s server UploadedComplete handler — and be aware UpdatePanel/partial-postback interactions can complicate file-upload flows. (ajaxcontroltoolkit6.rssing.com)

Move the save to UploadedComplete and add a small server-side dedupe check. Example (C#):

protected void AsyncFileUpload1_UploadedComplete(object sender, AjaxControlToolkit.AsyncFileUploadEventArgs e)
{
    // quick dedupe fingerprint (name + length). Use DB or persistent token for stronger guarantees.
    string fingerprint = e.FileName + "|" + AsyncFileUpload1.PostedFile.ContentLength;
    if (Session["LastUploadFingerprint"] != null &&
        Session["LastUploadFingerprint"].ToString() == fingerprint)
        return;
    Session["LastUploadFingerprint"] = fingerprint;

    string safeName = Path.GetFileName(e.FileName);
    string savePath = Server.MapPath("~/Uploads/") + Guid.NewGuid().ToString("N") + "_" + safeName;
    AsyncFileUpload1.SaveAs(savePath);
}

This keeps saving out of Page_Load and prevents a second save if the handler is triggered twice. The control exposes the usual server events and SaveAs() for persisting uploads. (ajaxcontroltoolkit6.rssing.com)

If the duplicate comes from refreshing the browser after a POST, break the POST chain (Post/Redirect/Get). With AsyncFileUpload you usually must do that on the client after the async upload completes (OnClientUploadComplete) because server-side Response.Redirect may only affect the upload iframe. Example client-side redirect:

<script type="text/javascript">
function onClientUploadComplete(sender, args) {
    // navigate to a GET result page or same page with a query flag to avoid re-submitting the POST
    window.location = window.location.pathname + "?uploaded=1";
}
</script>

PRG prevents the browser from resubmitting the POST on refresh. (en.wikipedia.org)

Troubleshooting checklist

  • Reproduce while watching Chrome/DevTools Network: are there two POST requests (two upload entries) or only one?
  • If you see two uploads immediately (not just after F5), search client scripts for doPostBack or a forced postback in OnClientUploadComplete — avoid forcing a raw doPostBack that causes the control to resend.
  • Add server logging (timestamp + Request headers) inside UploadedComplete to see how/when the handler runs.
  • As a last line of defense, deduplicate by filename+size/timestamp or use GUID prefixes when saving.

References: AjaxControlToolkit AsyncFileUpload docs for events/properties and guidance, and Microsoft UpdatePanel notes on file-upload caveats. (ajaxcontroltoolkit6.rssing.com)

Recommended Answers

All 3 Replies

Member Avatar for hericles

Hi,
With no code to go on I'm speculating but have you got the code to upload the file in the Page_Load method? if so, and you don't want the action repeated, you need to put the code inside of

if(!Page.IsPostBack) {
// your code
}

This means your code is only called the first time the page is loaded. Subsequent reloads (postbacks) skip the code.

Is that what you need?

Member Avatar for Ramesh S

Hi,

Hope the solution given in the following link will help you.

AsyncFileUpload postback causes double upload

Someone has reported the same issue in CodePlex site . But it is closed as the issue cannot be reproduced.

Member Avatar for crishlay

write condition if(!page.IsPostback) then "write you code " end if

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