Forms Data Controls :: UserControl In Page / Hiddenfield In Each Is Not Empty?

I have a repeater which always has 1 UserControl, however the UserControl can vary, lets say it could be UC1, UC2 or UC3.

When I come to validate that a hiddenfield in each is not empty, I iterate through the repeater items but I have to do a findcontrol on UC1 check an exposed value, then do the same for UC2 then UC3. In all its a bit unwieldly.

What it would be great to do is iterate through the repeater items find the hiddenfield (which is the same name for each UC) and test that in one go, like below:

foreach(RepeaterItem item in Repeater1)

{
... some code here to start off with

HiddenField hfAnswer = (HiddenField)item.FindControl("HF_Answer");
if(hfAnswer != string.Empty)
do something here
}