private void xButtonOpen_Click(object sender, RoutedEventArgs e)
{
OpenFileDialog dialog = new OpenFileDialog();
dialog.Multiselect = false;
dialog.FileOk += delegate(object s2, CancelEventArgs e2)
{
string fileName = dialog.FileName;
App.Current.MainWindow.RequestLoadUnknownFile(fileName);
};
dialog.ShowDialog();
}