custom ListView inside Update panel not refreshing - asp.net

Question

I'm trying to solve this problem.
I have an Accordion inside an UpdatePanel. Inside the Accordion control I dinamically create at most four AccordionPanes, each with a custom ListView that shows some image previews fetched from a database. Each preview is composed by a 160x120 ImageButton. When the user clicks on one of these buttons a popup is opened with the image at real size (by a Seadragon control); he can now rotate the image and save it back to the database. Now, after saving the image, I close the popup and submit a postback by generating a click event on a hidden button inside the UpdatePanel containing the Accordion, but even if I can step through the hidden button event code, the refresh doesn't take place. The hidden button was the last (and most effective) solution I've tried, without success. What am I missing ? (The absolute best solution would be refresh the only image that changed, because sometimes the ListView contains several previews).
This is the
<div>
<table class="style8">
<tr>
<td class="style2">
<asp:UpdatePanel ID="usersPanel" runat="server" >
<ContentTemplate>
<cc1:c1treeview ID="tvUsers" runat="server"
onselectednodeschanged="tvUsers_SelectedNodesChanged" AutoPostBack="True"
onnodecheckchanged="tvUsers_SelectedNodesChanged">
</cc1:c1treeview>
</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdatePanel ID="imagesPanel" runat="server" UpdateMode="Always" >
<ContentTemplate>
<asp:Button ID="hiddenImageRefresh" runat="server" Text="Refresh"
style="display:none;" onclick="hiddenImageRefresh_Click" />
<ajaxToolkit:Accordion ID="accImages" runat="server" >
</ajaxToolkit:Accordion>
</ContentTemplate>
</asp:UpdatePanel>
</td>
</tr>
</table>
</div>
And this is the code contained in the hidden button click event, code, that regularly runs when the popup closes. It simply extracts a user code (promo) and rebind the data (LoadImages)
protected void hiddenImageRefresh_Click(object sender, EventArgs e)
{
string promo = "";
if(Session[SessionVariables.CurrentPromoter] != null)
promo = Session[SessionVariables.CurrentPromoter].ToString();
LoadImages(promo, ddlImageType.SelectedValue);
}

Answer 1

Steps to refresh only updated image
Step#1: in JavaScript
//Take one global variable
var selectedImageId="";
Step#2: in JavaScript
//set above var with image id, When user clicks on the ImageButton, which is inside openPopup function
selectedImageId = this.id;
Step#3: in Code-Behind
protected void bSave_Click(object sender, EventArgs e) {
//SaveImage();
#region here get the imageUrl that needs to be updated and send as parameter in closePopup js function
var timeStamp = dImgTag.ToString("yyyyMMdd HH:mm:ss.fff") ;
var promoter = riga["PROMOTER"].ToString();
var pv = riga["PV"].ToString();
var imageUrl = string.Format("../Handlers/ImageLoader.ashx?id={0}&promo={1}&pv={2}", timeStamp, promoter, pv);
#endregion
ClientScriptManager csm = Page.ClientScript;
csm.RegisterStartupScript(Page.GetType(), "closeScript", "closePopup(true,'"+ imageUrl +"');", true);
}
Step#4: in JavaScript
function closePopup(refreshParent, imageUrl) {
if (refreshParent) {
//get the selectedImage and set the source with new url
var selectedImage = window.opener.document.getElementById(selectedImageId);
selectedImage.src = imageUrl;
}
window.close();
}