<UserControl x:Class="SilverlightApplication3.SilverlightControl1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Width="400" Height="300">
    <Grid x:Name="LayoutRoot" Background="White">
        <TextBox Name="TextBox1"/>
    </Grid>
</UserControl>
