You can expose a public method in your user control to any page that uses the control. You should also add an event to alert the parent pages if the state changes. Adding these methods are easy enough:
Partial Class user_controls_myControl
Inherits System.Web.UI.UserControl
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
End sub
Public Function isValid() as boolean
if(me.checkbox1.text<>"" andalso me.checkbox2.text<>"") then
return true
else
return false
end if
End sub
end Class
Now, in your ASPX page that holds all of these controls, you can check that specific function to make sure they are valid. For instance, if you have a user control called giveIdentity1, you'll want to iterate over the repeater and cast an object to your user control type. You can then check the isValid function like this:
dim getBool as boolean
getBool = me.giveIdentity1.isValid
If you need help iterating over the repeater, let me know
You can also create your own server events to register changes. You can read a post to a similar topic I responded to here: Handling events of usercontrols within listview
If this does not answer your question, let me know.