Using AJAX.NET how do you clear an uploadfile control?

Posted on 2011-02-15
Last Modified: 2012-06-27
I have a regular upload file control inside an AJAX.NET updatepanel.  If I use it to upload a file once, its no problem; however, if i hit the submit button again, even though the text box is clear, it is still attached to the previous file uploaded.

How do I clear that so that I may use the uploadfile control freshly?
Question by:RichardRiga
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 2
  • 2
LVL 16

Accepted Solution

Kamal Khaleefa earned 250 total points
ID: 34904109

Author Comment

ID: 34910571
That's a neat article but how do I call a javascript function after the .NET webservice code has completed its work?
LVL 16

Expert Comment

by:Kamal Khaleefa
ID: 34914764
regarding to Ur  question
but a JavaScript function to see if the file upload is empty

 var FileUpload1="<%=FileUpload1.ClientID %>"
function CheckForTestFile()
        var file = document.getElementById(FileUpload1);
        var fileName=file.value;        
        //Checking for file browsed or not
        if (Trim(fileName) =='' )
            alert("Please select a file to upload!!!");
            return false;
and on ur button
add this

 <asp:Button ID="btnUpload" runat="server"  OnClientClick="if(CheckForTestFile()){return true}else{return false}"
                                                  text="Upload File" TabIndex="50" EnableViewState="False" />
Online Training Solution

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action. Forget about retraining and skyrocket knowledge retention rates.


Author Comment

ID: 34916726
These methods don't seem to work still.  I have inserted them into the proper places and they are being executed; however, the fileupload control still reports that it has contents when trying to upload a blank file'

Author Comment

ID: 34917036
My apologies!!  I completely forgot to mention that I wasn't using an ASP:FileUpload control.  I'm using the AsyncFileUpload control from the AjaxToolkit.  I'm not sure it makes a difference in your answers;however, I should have added that.
LVL 83

Assisted Solution

CodeCruiser earned 250 total points
ID: 34917067
>however, the fileupload control still reports that it has contents when trying to upload a blank file'
Do you mean you are uploading a 0 byte file?

Author Comment

ID: 34918554
Here is what happens:

1.  I use the control to upload a file.  That works, no problem.  
     At this point the control's field resets itself to appear empty.
     Since the field is empty, at this point, if I hit the submit button again, the property fuFileUpload.HasFile should be False.  But its not.  It returns true.

2.  So i use a script:
            function clearContents() {
                 var AsyncFileUpload = $get("<%=fuFileUpload.ClientID%>");
                 var txts = AsyncFileUpload.getElementsByTagName("input");
                 for (var i = 0; i < txts.length; i++) {
                     if (txts[i].type == "text") {
                         txts[i].value = "";
                         txts[i].style.backgroundColor = "white";

and call on that script when the file is uploaded with:
<cc1:AsyncFileUpload ID="fuFileUpload" runat="server" OnClientUploadComplete="<%UploadComplete() %>" />

Codebehind has:
    Public Sub CallUploadComplete()
        ClientScript.RegisterStartupScript(Me.GetType(), "removeDoc", "ClearContents()", True)
    End Sub

Something isn't right.  Can anyone fix those three snippets of code to make it work?  I beg!  
And thanks.

Open in new window

LVL 83

Expert Comment

ID: 34924555
What does the



Author Closing Comment

ID: 35028696
Project was scrapped.  Apologies for the waste of time, but thank you for being respondent

Featured Post

MS Dynamics Made Instantly Simpler

Make Your Microsoft Dynamics Investment Count  & Drastically Decrease Training Time by Providing Intuitive Step-By-Step WalkThru Tutorials.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
ASP.NET Calendar Control 5 26
Provide the IDEA of External JS 1 39
ASP.NET Built-In Report Creator / Viewer 5 25
Need help with a query 14 39
Parsing a CSV file is a task that we are confronted with regularly, and although there are a vast number of means to do this, as a newbie, the field can be confusing and the tools can seem complex. A simple solution to parsing a customized CSV fi…
If you need to start windows update installation remotely or as a scheduled task you will find this very helpful.
Finds all prime numbers in a range requested and places them in a public primes() array. I've demostrated a template size of 30 (2 * 3 * 5) but larger templates can be built such 210  (2 * 3 * 5 * 7) or 2310  (2 * 3 * 5 * 7 * 11). The larger templa…
In an interesting question ( here at Experts Exchange, a member asked how to split a single image into multiple images. The primary usage for this is to place many photographs on a flatbed scanner…

733 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question