I have a button in a usercontrol that I was to set as the Id for a trigger in the update panel.

Is this possible and how do I achieve this? I cant seem to figure out how to expose the button on the .aspx page.

You have to declare an event in the user control. And in usercontrol .cs you raise the declared event in th onclick event of the user control.
And in your .aspx page you add the UserControl as Trigger ControlId and the event you have declared in the UserControl as the EventName of the AsyncPOstBackTrigger

Sample Code:(Test.aspx)
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<%= DateTime.Now.ToString()%>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="WebUserControl1" EventName="CausePostBack" /> </Triggers>
</asp:UpdatePanel>
<uc1:WebUserControl id="WebUserControl1" runat="server">
</uc1:WebUserControl>

UserControl Code: (.ascx)
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="WebUserControl.ascx.cs" Inherits="WebUserControl" %>This is a test
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />

(.cs)
protected void Button1_Click(object sender, EventArgs e)
{  CausePostBack(sender, e);  }
public event EventHandler CausePostBack;


Please Don't forget to click on MarkAsAnswer if this helps you

While this works for a AsyncPostBackTrigger it does not completly solve my problem as I need to use a PostBackTrigger.

See the user control is a file upload control and you cant upload the file using the AsyncPostBack as it needs to be a PostBack which is why i need to get this to work for a postbacktrigger.

 Any suggestions? 

Well I guess its really no different. You just make the trigger a postbacktrigger and then set the controlId = to the usercontrol.

 Seems to work so far on a test page. I'll integrate this into my page and see how it goes.

Hi,

Thank you for your post!

I think the main issue is that the button is in another UserControl, so the question is "How to Trigger PostBack to an UpdatePanel from a separate UserControl?  ", This link mentioned a workground for it.

But I think the best solution is to Bubble the Click Event of the button to a custom event of UserControl.then specify the custom event as a Trigger for the update panel.

See these links:

1. Bubble Event from UserControl
2. Can I specify a UserControl custom event as a Trigger for update panel on Parent page?

Ok,Hope these help you!

Best Regards