how to assign target control to validator control on serverside

I am having N numbers of Text boxes those are generating dynamically. I want to validate each textbox for Formate HH:MM:SS PM/AM so i dynamicaly create开发者_StackOverflow the validation control . but as the dynamic textbox has no ID , so what i have to pass to the Validation control for ControlToValidate Property ?

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AccordionPane ap1; for (int i = 0; i <= 2; i++) { ap1 = new AccordionPane(); ap1.HeaderContainer.Controls.Add(new LiteralControl("Using Markup")); Panel pnl = new Panel();

                TextBox txtTime = new TextBox();
                txtTime.ID = "txtTimeBox" + i;
                txtTime.ValidationGroup = "MKE";
                RegularExpressionValidator validateDate = new RegularExpressionValidator();
                validateDate.ValidationExpression = "(0[1-9]|1[0-2]):([0-5][0-9]):([0-5][0-9]|60) (AM|PM|am|pm)";
                validateDate.ControlToValidate = txtTime.ID;
                validateDate.ErrorMessage = "Invalid Date. Try in HH:MM:SS AM/am|PM/pm format";

                pnl.Controls.Add(txtTime);
                ap1.ContentContainer.Controls.Add(pnl);
            MyAccordion.Panes.Add(ap1);
        }
        Page.Controls.Add(divContainer);