ASP.NET Controls in UpdatePanel not working after File Upload - asp.net

Question

I'm new to working with the AJAX UpdatePanel and I've tried searching for an answer to this question and haven't found a solution yet.
I have multiple controls in an UpdatePanel since I am hiding and showing panels based on different button clicks. Also inside the UpdatePanel is a FileUpload control. Everything works fine until I upload a file. After that, none of the controls, like buttons or radio button lists, or JQuery scripts, like a datepicker, fire in the UpdatePanel after the upload.
Here is the aspx code:
<%# Page Title="" Language="C#" MasterPageFile="~/Site1.Master" AutoEventWireup="true" CodeBehind="Admin.aspx.cs" Inherits="Site.Admin" %>
<%# MasterType virtualPath="~/Site1.master"%>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js"></script>
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/smoothness/jquery-ui.css">
<script src="//code.jquery.com/jquery-1.12.4.js"></script>
<script src="//code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<script type="text/javascript" src="scripts/jquery-ui-timepicker-addon.js"></script>
<link rel="stylesheet" href="Content/jquery-ui-timepicker-addon.css">
<script type="text/javascript">
function pageLoad() {
$(function () {
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
function EndRequestHandler(sender, args) {
$('.picker').datetimepicker();
}
});
}
</script>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="True"></asp:ScriptManager>
<asp:UpdatePanel ID="adminUpdatePanel" UpdateMode="Conditional" ChildrenAsTriggers="True" runat="server">
<ContentTemplate>
<div class="form-group">
<div class='input-group date' id='datetimepicker3'>
<asp:TextBox ID="tb_EndDate" class="form-control picker" runat="server"></asp:TextBox>
<span class="input-group-addon">
<span class="glyphicon glyphicon-calendar"></span>
</span>
</div>
</div>
<div class="form-group">
<asp:RadioButtonList ID="rbl_Active" runat="server" OnSelectedIndexChanged="rbl_Active_SelectedIndexChanged" RepeatDirection="Horizontal" CellPadding="4" CellSpacing="4" AutoPostBack="True">
<asp:ListItem>Yes</asp:ListItem>
<asp:ListItem>No</asp:ListItem>
</asp:RadioButtonList>
</div>
<div class="form-group">
<label>Upload Photo</label>
<asp:FileUpload ID="imageFileUpload" runat="server" />
<asp:Button class="btn btn-primary" ID="btn_UploadImg" runat="server" Text="Upload Image" OnClick="btn_UploadImg_Click" CausesValidation="False" />
<asp:Button ID="btn_CancelImg" OnClick="btn_CancelImg_Click" class="btn btn-primary" runat="server" Text="Change/Remove Image" CausesValidation="False" />
</div>
</ContentTemplate>
</asp:UpdatePanel>
</asp:Content>
And the code behind relating to the file upload:
protected void Page_Load(object sender, EventArgs e)
{
ScriptManager.GetCurrent(this).RegisterPostBackControl(this.btn_UploadImg);
}
protected void btn_UploadImg_Click(object sender, EventArgs e)
{
bool isUploaded = uploadImage(imageFileUpload);
if (isUploaded)
{
btn_CancelImg.Visible = true;
}
}
I'm not sure what I'm doing wrong. It worked fine when run from Visual Studio, but when pushed to the server it all fails

Answer 1

Instead of setting Visible to true/false, can you please try:
<asp:Panel ID="pnlToHide" runat="server" style="display:none">
When you have to show, you can use the following:
protected void btnShow_Click(object sender, EventArgs e)
{
pnlToHide.Attributes["style"] = "display: '';";
}
Also, you can try fullpostback/render by using:
<Triggers>
<asp:PostBackTrigger ControlID="btnFileUpload"/>
</Triggers>