Principal.cs

using System;
using System.Windows;
using System.Windows.Forms;
using System.Windows.Forms.Integration;
using WPFControls = System.Windows.Controls;

namespace R722ControlWPFEnWinForms
{
    public partial class Principal : Form
    {
        WPFControls.TextBox txtRegistroCambioColor;
        private ElipseControl elipseControl;

        public Principal()
        {
            InitializeComponent();

            txtRegistroCambioColor = new WPFControls.TextBox();
            txtRegistroCambioColor.Text = "Campo de Texto WPF\n\r\n\r";
            txtRegistroCambioColor.TextAlignment = TextAlignment.Center;
            txtRegistroCambioColor.VerticalAlignment = VerticalAlignment.Center;
            txtRegistroCambioColor.VerticalScrollBarVisibility = WPFControls.ScrollBarVisibility.Auto;
            txtRegistroCambioColor.IsReadOnly = true;

            ElementHost elhContedorCampoTexto = new ElementHost();
            elhContedorCampoTexto.Name = "elhContedorCampoTexto";
            elhContedorCampoTexto.Dock = DockStyle.Fill;
            elhContedorCampoTexto.Child = txtRegistroCambioColor;
            elhContedorCampoTexto.Size = new System.Drawing.Size(156, 253);
            elhContedorCampoTexto.RightToLeft = RightToLeft.No;

            tlpContenedor.Controls.Add(elhContedorCampoTexto, 0, 0);


            elipseControl = new ElipseControl();

            elhElipse.Child = elipseControl;

            btnCambiarColorElipse.Anchor = AnchorStyles.None;
        }

        private void btnCambiarColorElipse_Click(object sender, EventArgs e)
        {
            elipseControl.CambiarColor();

            txtRegistroCambioColor.Text += String.Format("La elipse cambió su color a {0}\n\r", elipseControl.Color);

            txtRegistroCambioColor.ScrollToEnd();
        }
    }
}