private void btnLoad_Click(object sender, EventArgs e)
        {
            if (_metadata != null)
            {
                OpenFileDialog dlg = new OpenFileDialog();
                dlg.Filter = "Xml Datei|*.xml";

                if (dlg.ShowDialog() == DialogResult.OK)
                {
                    XmlStream stream = new XmlStream("TileService");
                    stream.ReadStream(dlg.FileName);
                    _metadata.Load(stream);

                    this.Parameter = _metadata;
                }
            }
        }