I whipped up a quick SL3 app and it is difficult to have the initial focus go to the UserControl let alone to a control within the Silverlight control.
However, see if this solution solves this issue for you. You'll have to use a little JavaScript.
Here's the code for reference:
<%@ Page Language="C#" AutoEventWireup="true" %>
<%@ Register Assembly="System.Web.Silverlight" Namespace="System.Web.UI.SilverlightControls"
TagPrefix="asp" %>
<!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" style="height:100%;">
<head runat="server">
<title>Test Page For TextFocusTest</title>
<script type="text/javascript">
window.onload = function()
{
document.getElementById('Xaml1').focus();
}
</script>
</head>
<body style="height:100%;margin:0;">
<form id="form1" runat="server" style="height:100%;">
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<div style="height:100%;">
<asp:Silverlight ID="Xaml1" runat="server" Source="~/ClientBin/TextFocusTest.xap" Version="2.0" Width="100%" Height="100%" />
</div>
</form>
</body>
</html>
Once your SL control has focus, you can further set the focus to a specific control using something like:
namespace SilverlightApplication2
{
public partial class MainPage : UserControl
{
public MainPage ()
{
InitializeComponent ();
this.GotFocus += new RoutedEventHandler (MainPage_GotFocus);
}
void MainPage_GotFocus (object sender, RoutedEventArgs e)
{
uxLogin.Focus ();
}
}
}
where uxLogin is defined in XAML as:
<TextBox x:Name="uxLogin" Height="25" Width="100" />