Storyboard で、textBoxの TranslateTransform を変更

SetTargetPropertyあたりのプログラミングで、どのように表記すればいいのかが分からず難しい。

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;

namespace wpfsbtest1
{
    /// <summary>
    /// Window1.xaml の相互作用ロジック
    /// </summary>
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
            Play1();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            translateTransform1.BeginAnimation(TranslateTransform.XProperty, daukf);
        }

        Storyboard myStoryboard1 = new Storyboard();

        DoubleAnimationUsingKeyFrames daukf = new DoubleAnimationUsingKeyFrames();

        TranslateTransform translateTransform1 = new TranslateTransform();
        private void Play1()
        {
            textBox1.RenderTransform = translateTransform1;

            SplineDoubleKeyFrame sdkf1 = new SplineDoubleKeyFrame(0, KeyTime.FromTimeSpan(new TimeSpan(0, 0, 0)));
            SplineDoubleKeyFrame sdkf2 = new SplineDoubleKeyFrame(200, KeyTime.FromTimeSpan(new TimeSpan(0, 0, 3)));

            daukf.BeginTime = new TimeSpan(0, 0, 0);
            daukf.Duration = new TimeSpan(0, 0, 3);
            daukf.KeyFrames.Add(sdkf1);
            daukf.KeyFrames.Add(sdkf2);

            Storyboard.SetTargetName(daukf, this.textBox1.Name);
            Storyboard.SetTargetProperty(daukf, new PropertyPath(TranslateTransform.XProperty));

            myStoryboard1.Children.Add(daukf);
        }
    }
}