Use value from form in server-side script : The Official Microsoft ASP.NET Forums

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ruth_l

0 Points

Use value from form in server-side script

Feb 28, 2012 02:10 PM|LINK

I am new to the AJAX world, and have been given an ASP page, with javascript that contains dojo, and asked to use some AJAX on it. I thought the ASP.net AJAX solution would be simple enough - just use the UpdatePanel... but maybe I'm wrong :-) So, I added an UpdatePanel to the ASP.net page, and there's an "Upload" button that calls a server-side script. In the server-side script method, I need to access the value in a FileUpload object ("pdf_file"). However, the FileUpload object doesn't have a value when the server-side script accesses it (even though I selected a value, and it shows in the FileUpload box). From what I understand, the "object" passed to the method is now the Control, instead of the Page, since I'm using the UpdatePanel. So, I tried getting the Parent of the "object" (Control), etc, but there still wasn't a value. I have Googled my heart out for an answer to this, and can't seem to figure it out. Any help would be greatly appreciated!

Here's the ASP page...

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Test._Default" Async="true" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Demo</title>
    <script type="text/javascript" src="./js/main.js"></script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        
        <asp:ScriptManager ID="MainScriptManager" runat="server" EnablePartialRendering="true" />
        <asp:UpdatePanel ID="pnlTable" runat="server" UpdateMode="Conditional" ChildrenAsTriggers="false">
            <ContentTemplate>
                <asp:FileUpload ID="pdf_file" runat="server" />
                <br /><br />
                <asp:Label runat="server" id="status_label" text="" />
                <asp:HiddenField ID="hidden_products" runat="server" />
                <asp:GridView ID="grid" runat="server" onrowdatabound="grid_RowDataBound"
                    onselectedindexchanged="grid_SelectedIndexChanged">

                </asp:GridView>
                <asp:Button ID="upload_button" runat="server" Text="Upload" onClientClick="submit();" onclick="upload_button_Click" />
            </ContentTemplate>
            <%-- <Triggers>
                <asp:AsyncPostBackTrigger ControlID="upload_button" EventName="Click" />
            </Triggers>  --%>
        </asp:UpdatePanel>
</div></form></body></html>

Here's the (first part of the) server-side method...

protected void upload_button_Click(object sender, EventArgs e)
{
    //Control ctl = (Control)sender;
    //String ctlType = ctl.Parent.GetType().ToString();
    //HtmlForm form = (HtmlForm)ctl.Parent;
    //FileUpload pdfUpload = (FileUpload)form.FindControl("pdf_uploader");
    //lblStatus.Text = "upload_button_Click";
    
    if (pdf_uploader.HasFile)
    {
        string file_name = pdf_uploader.FileName;
        // Save temp copy of pdf on server
        Random random_gen = new Random();
        int rand = random_gen.Next();
        string temp_pdf_path = "c:/temp/base_pdf_" + rand + ".pdf";
        pdf_uploader.SaveAs(temp_pdf_path);

        IEnvelope aoi = Get_Extent(temp_pdf_path, temp_xml_path,true);
    }
}

Reply

breath2k

Contributor

2101 Points

821 Posts

Re: Use value from form in server-side script

Feb 28, 2012 03:52 PM|LINK

I had the same problem, in the end I used a jQuery file upload tool like this one:

http://blueimp.github.com/jQuery-File-Upload/

Suggest you try the same but have a look at other plugins too that might suit your needs better.

Marked as answer by BU XI - MSFT on Mar 05, 2012 02:00 AM

Reply

chetan.sarod...

All-Star

65749 Points

11148 Posts

Re: Use value from form in server-side script

Feb 29, 2012 02:20 AM|LINK

File upload doesn't work with updatepanels. It's a known issue and the latest AJAX Control Toolkit has an AsyncFileUpload control to remedy this problem.

Refer: http://www.asp.net/ajax/ajaxcontroltoolkit/Samples/AsyncFileUpload/AsyncFileUpload.aspx

See here building AJAX enabled File Upload control

http://aspalliance.com/1442_Building_AJAX_Enabled_File_Uploading_System_with_Progress_Bar_Using_ASPNET_20.all

http://geekswithblogs.net/rashid/archive/2007/08/01/Create-An-Ajax-Style-File-Upload.aspx

http://weblogs.asp.net/manojkdotnet/archive/2009/10/16/asynfileupload-control-and-its-validation.aspx

http://msmvps.com/blogs/luisabreu/archive/2006/12/14/uploading-files-without-a-full-postback.aspx

http://blogs.infragistics.com/blogs/tony_lombardo/archive/2007/04/09/file-uploads-where-s-the-ajax.aspx

http://www.codeproject.com/KB/aspnet/AJAXUpload.aspx

http://forums.asp.net/t/1207035.aspx

Chetan Sarode
Senior Software Engineer,
Approva Systems Pvt Ltd, Pune, India.