private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        DataRow[] result = ds.Tables["AssessmentItems"].Select("GroupId = " + listBox1.SelectedIndex);

        var newTable = result.CopyToDataTable();
        BindingSource bindSource = new BindingSource();
        bindSource.DataSource = newTable;
        dataGridView1.DataSource = bindSource;
    }