How to access Dynamically Generated Controls not knowing their names - asp.net

Question

My page generates a list of check boxes at run time. I set the Id of each of these boxes manually by assigning to each the string.Format("checkbox_{0}, n} where n is a running number.
How to I find out the list of checkbox controls from codebehind? I couldn't find them in Page.Form.Controls. Where are they placed?
(I can see the checked checkboxes in Request.Form but that contains client side names of each control.)
Thanks.
-
---More info----
My iterative loop Adds CheckBoxes to a Panel control (created in the mark-up page) as follows:
CheckBox checkbox = new CheckBox();
checkbox.Text = "Add to list";
checkbox.ID = string.Format("checkbox_{0}", n.ToString("0"));
Panel1.Controls.Add(checkbox);
The checkboxes show up nicely on the page. I can tick. When I submit the Http POST stream contains all those ticked ones.
On post back, Panel1.Controls.Count is 0. When the page was first generated, Panel1.Controls.Count was 200, as it contained lots of LieteralControls for layout.

Answer 1

You can use the findcontrol method on page object or parent control object to find that checkbox object. like:
CheckBox chx=(CheckBox)Page.FindControl("Checkbox1");
if(chx!=null)
chx.Checked = false;
you can put this insode the loop also like:
for(int i=0;i<n;i++)
{
CheckBox chx=(CheckBox)Page.FindControl("Checkbox"+n);
if(chx!=null)
chx.Checked = false;
}

Answer 2

On post back, Panel1.Controls.Count is 0. When the page was first generated, Panel1.Controls.Count was 200, as it contained lots of LieteralControls for layout.
If you add controls dynamically in this way, you need to add them again (same ids, same order) on each postback.
Which means you need to persist whatever info you need to add them again. For example, you could store the number of checkboxes in ViewState, then regenerate that number of checkboxes on each post back.