how can i get control inside the user control from the master page or page ?

hi all
1. i ahve an master page called "Site2.Master".
2. i have an user control called "US1".
3. i have an page called "webform2.aspx" and it use the master page "Site2.Master" and i have add the user control "US1" on this page.
my user control HTML is:
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="US1.ascx.cs" Inherits="WebApplication3.WebUserControl1" %> <%@ Register Assembly="DevExpress.Web.ASPxHtmlEditor.v13.1, Version=13.1.8.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" Namespace="DevExpress.Web.ASPxHtmlEditor" TagPrefix="dx" %> <dx:ASPxHtmlEditor ID="HtmlEditor" runat="server" EnableCallbackAnimation="True" Theme="MetropolisBlue" ...