Hello!

I'm creating a custom WebControl that have an UpdatePanel inside. On client side I have a js-based UpdatePanel postback (code below) and I want to catch an event in my control when the UpdatePanel is posted back to the server. The thing is that I want to raise another event from my control in a reaction. Are there any "standard" ways to do that?

As a workaround I can place a HiddenField inside UpdatePanel and change its value before posting back an UpdatePanel, then catch HiddenField.Changed event in my control, but I want to avoid such solution as much as possible.

JS class method for update UpdatePanel (where this.updatePanel is the updatePanel control)

	postBack : function()
	{
		var prm = Sys.WebForms.PageRequestManager.getInstance();
		prm._doPostBack (this.updatePanel.id, '');
	}

You'll have to implement IPostbackEventHandler interface if you want to enable event handling in your control. I think that should be enough to get it working.

See if this helps you out: http://encosia.com/index.php/2007/07/13/easily-refresh-an-updatepanel-using-javascript/

-Damien

Also, check out this post: http://forums.asp.net/t/1151141.aspx

-Damien

Thank you guys! 

 Sujit,

Yes, I indeed tried implementing IPostbackEventHandler, but for some strange reason, RaisePostbackEvent was never called. Probably there's something wrong with my understanding of how it works.

 Damien,

Actually prm._doPostBack is invoked through __doPostBack, so approaches are pretty the same.

Finally, I came to conclusion to override UpdatePanel class (anyway I needed to add some CSS class styling to it) and override its RenderChildren method to analyze IsInPartialRendering property and raise an event if needed.

What I actually wanted is to create a custom Web control that allows creation the contents of UpdatePanel dynamically through events it issues. In my case building contents can be quite time consuming, that's why I want to do it only when the UpdatePanel actually gets updated.