Page update after asyncfileupload completes upload - ajax

Question

I see this question asked frequently and I have done extensive experimentation to try to get this to work. However everyone else's examples and answers have so far failed me. I am bemused. Here is the situation:
AsyncFileUpload is NOT in an UpdatePanel
Image and Label to be updated are in an UpdatePanel
Update should occur after the upload completes
The upload is indeed saving the file as expected. My problem is regarding getting the page to update after that happens. The file being uploaded is an image, and I would like that image to update. I am aware of some problems with images not updating on the client if you reuse filenames, but I am also printing it to a label just to be sure. I am certain the UpdatePanel I am targeting is not updating.
I have tried the following approaches:
Using the server side method to manually update a conditional UpdatePanel - this fails because the file upload is done in a frame. Sniffing the returned HTML shows that the correct HTML is actually sent back after the post, but of course to the wrong frame.
Using the client side method to trigger a javascript postback to my UpdatePanel. This does not work and I cannot tell why.
Using the client side method to trigger a javascript button click inside the UpdatePanel. Again, nothing happens and I don't know why.
Setting the UpdatePanel's trigger up so that it points directly at the AsyncFileUpload. No joy, but I knew that would be a long shot, keeping in mind the hidden frame.
Moving the AsyncFileUpload into the UpdatePanel and trying some variety of the above. When I do this, I lose all handle of the file being posted to the server and I cannot save the file in the first place.
Normally when I get this kind of error, where all the tutorials appear to be wrong, it turns out that my error is because I didn't set an ID on a control somewhere and it somehow mattered. I can't even see that in this case. Here is some code.
<fieldset class="pj_Pics">
<ul>
<li>
<label>Picture 1</label>
<asp:UpdatePanel ID="ajax_Pic1" runat="server" UpdateMode="Always">
<ContentTemplate>
<asp:Image ID="img_Pic1" runat="server" />
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
<asp:Button ID="Button1" runat="server" Text="Button" />
</ContentTemplate>
</asp:UpdatePanel>
<div style="position:relative;">
<div class="photoChooser">
<ajaxToolkit:AsyncFileUpload ID="fu_Pic1" runat="server" CssClass="pj_PicChoose" Width="84px" OnClientUploadComplete="picPost1" OnUploadedComplete="fu_PictureFile_UploadedComplete" ThrobberID="throb1" />
<span><asp:Literal runat="server" Text="click to change"></asp:Literal></span>
<asp:Image ID="throb1" runat="server" ImageUrl="~/images/throbber.gif" AlternateText="uploading image" />
</div>
</div>
</li>
</ul>
</fieldset>
protected void fu_PictureFile_UploadedComplete(object sender, AjaxControlToolkit.AsyncFileUploadEventArgs e)
{
bla bla bla;
// and update the image
img.ImageUrl = "~/" + webfolder + imageFileName;
thing.Text = img.ImageUrl;
}
function picPost1(sender, args) {
document.getElementById('<%# Button1.ClientID %>').click();
}
Any help greatly appreciated. There is obviously a ScriptManager on the page and the code I've shown is just the last thing I have attempted. Let me know if there is anything else you need to see.
Thank you!

Answer 1

I happen to face the same situation today, and this is how I solved it.
According to this LINK, there's no Postback is happening or even a ViewState since its Asynchronous FileUpload.
So in OnUploadedComplete I test file type and size before executing the SaveAs() in codebehind, then I test the same in OnClientUploadComplete to display messages and carry on the rest of the work like setting Images URL. Hope this helps.