How to load a button below the SfDataGrid in RelativeLayout?

protected override void OnCreate(Bundle bundle)
{
      base.OnCreate(bundle);
      viewModel = new ViewModel();
      grid = new SfDataGrid(this);
      add_row = new Button(this.BaseContext);
      grid.Id = 1;
      grid.ItemsSource = viewModel.Info;
      RelativeLayout relative = new RelativeLayout(this.BaseContext);
      RelativeLayout.LayoutParams param = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MatchParent, ViewGroup.LayoutParams.WrapContent);
      param.AddRule(LayoutRules.AlignBottom,1);
      relative.LayoutParameters = param;
      add_row.SetBackgroundColor(Color.Navy);
      add_row.Text = "Add Row";
      add_row.Click += Add_row_Click; 
      relative.AddView(grid, ViewGroup.LayoutParams.MatchParent, 1000);
      relative.AddView(button, param);
      SetContentView(relative);
}
 
private void Add_row_Click(object sender, System.EventArgs e)
{
      viewModel.AddRow();
}