Adding UserControl dynamically map

Question

At WPF ESRI, we can add picture to the coordinate ,but we can not add with user control And I want to add "user control" to specify place at runtime. I hope that you understood what I mean.

        BitmapImage Bi = new BitmapImage(new Uri(st));

        PictureMarkerSymbol pms = new PictureMarkerSymbol()
        {
            Source = Bi
        };

        var graphic = new Graphic() { Geometry = new MapPoint(x, y) };
        graphic.Symbol = pms;
        MarkerGraphicsLayer.Graphics.Add(graphic);