Here you are.
Page
<%@ Page Language="C#" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<%@ Register Src="~/TestUC.ascx" TagPrefix="uc" TagName="TestUC" %>
<script runat="server">
[DirectMethod]
public void TestDirectMethod()
{
X.Msg.Alert("DirectMethod", "Hello from Page!").Show();
}
</script>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Ext.NET Example</title>
</head>
<body>
<form runat="server">
<ext:ResourceManager runat="server" />
<uc:TestUC runat="server" />
</form>
</body>
</html>
User Control
<%@ Control Language="C#" %>
<ext:Button runat="server" Text="Call Page's DirectMethod">
<Listeners>
<Click Handler="Ext.net.DirectMethods.TestDirectMethod();" />
</Listeners>
</ext:Button>