WPF

<Window x:Class="Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:UserControlDemo"
    Title="Window1" Height="300" Width="300">
    <Window.Resources>
        <DataTemplate DataType="{x:Type local:SimpleUserControlModel}">
            <local:SimpleUserControl />
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <HeaderedContentControl Name="hcControl"  Margin="20" Content="{x:Type local:SimpleUserControl}" 
                                    Height="auto" Width="auto" VerticalContentAlignment="Stretch"  />
    </Grid>
</Window>

Class Window1 
    Private _simpleModel As SimpleUserControlModel

    Public Sub New()

        ' This call is required by the Windows Form Designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        _simpleModel = New SimpleUserControlModel
        hcControl.Content = _simpleModel
    End Sub
End Class

<UserControl x:Class="SimpleUserControl"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >
    <Grid>
            <Border Margin="5" BorderThickness="5" BorderBrush="Red" />
    </Grid>
</UserControl>

Public Class SimpleUserControlModel
End Class

<br />
            protected override void OnRender(DrawingContext drawingContext)<br />
            {<br />
<br />
                if (this.Text != "")<br />
                {<br />
                    this.Background = new SolidColorBrush(Colors.Transparent);<br />
                    <br />
                    FormattedText formattedText = new FormattedText(<br />
                      this.Text,<br />
                        System.Threading.Thread.CurrentThread.CurrentCulture,<br />
                       FlowDirection.LeftToRight,<br />
                        new Typeface(this.FontFamily,this.FontStyle, this.FontWeight,this.FontStretch),<br />
                       this.FontSize, Brushes.Black<br />
                        );  //Text that matches the  textbox's<br />
<br />
<br />
                    double leftMargin = 4.0 + this.BorderThickness.Left;<br />
                    double topMargin = 2 + this.BorderThickness.Top;<br />
<br />
                    formattedText.MaxTextHeight = Math.Max(this.ActualHeight + this.VerticalOffset, 0); //Adjust for scrolling<br />
                    drawingContext.PushClip(new RectangleGeometry(new Rect(0, 0, this.ActualWidth, this.ActualHeight)));//restrict text to textbox<br />
<br />
<br />
                    List<Pair> ranges = dec.Ranges(this.Text);<br />
                    foreach (Pair p in ranges)<br />
                    {<br />
                        formattedText.SetForegroundBrush(Brushes.Blue, p.Start, p.Length);<br />
                        formattedText.SetFontWeight(FontWeights.Bold, p.Start, p.Length);<br />
                        <br />
                    }<br />
<br />
<br />
                    drawingContext.DrawText(formattedText, new Point(leftMargin - this.HorizontalOffset-2,topMargin));<br />
                }<br />
                //base.OnRender(drawingContext);<br />
            }<br />