Focus on a FrameworkElementFactory in WPF

Question

I am using a FrameworkElementFactory as the following code in my WPF program:

FrameworkElementFactory txt1 = new FrameworkElementFactory(typeof(TextBox));

I tried to programmatically focus on this FrameworkElementFactory and also tried it with VisualTreeHelper.HitTest. Is there any way to focus on *txt1 * like txt1.Focus or HitTest ?

I created it on Listview and filled in its columns programmatically. And design this Listview according to the following codes:

 for (int x = 0; x <= obj.ClmnDegerler.Length - 1; x++)
      {
        var GridViewColumn1 = new GridViewColumn();
        txt1 = new FrameworkElementFactory(typeof(TextBox));
        txt1.SetValue(TextBox.HeightProperty, 20.0);
        txt1.SetValue(TextBox.WidthProperty, clmnwidth);

        dataTemplate = new DataTemplate();
        dataTemplate.VisualTree = txt1; 

        GridViewColumn1.CellTemplate = dataTemplate;
        this.UGridview1.Columns.Add(GridViewColumn1);
      }

And I created a button by xaml and when I want to click the button I want to focus on txt1

private void Button_Click(object sender, RoutedEventArgs e)
        {
            //txt1.Focus(); not working
        }