How to locate control nested inside of another control

Finding
controls within a Page's control hierarchy can be painful but if you
know how the controls are nested you can use the lesser known "$"
shortcut to find controls without having to write recursive code. The
following example shows how to use the DefaultFocus property to set the
focus on a textbox that is nested inside of a FormView control. Notice
that the "$" is used to delimit the nesting:

<form id="form1" DefaultFocus="formVw$txtName" runat="server">
<div>
<asp:FormView ID="formVw" runat="server">
<ItemTemplate>
Name:
<asp:TextBox ID="txtName" runat="server"
Text='<%# Eval("FirstName") + " " + Eval("LastName") %>' />
ItemTemplate>
asp:FormView>
div>
form>

This little trick can also be used on the server-side when calling FindControl():

TextBox tb = this.FindControl("form1$formVw$txtName") as TextBox;
if (tb != null)

{
//Access TextBox control
}