GridPanel change selection in direct event doens't work

[Spamme]

Hello

I've taken this example https://examples2.ext.net/#/GridPane...box_Selection/ and added a button to change the selection with a direct event but it doesn't work, is it normal?

protected void ChangeSelection_Click(object sender, DirectEventArgs e)
{
  RowSelectionModel sm = this.GridPanel1.GetSelectionModel() as RowSelectionModel;
  for (var num1 = 1; num1 < 10; num1++) sm.SelectedRows.Add(new SelectedRow(num1.ToString()));
}

I have tried to rebind also the data source but it didn't work too.