如何更改DataGrid行的背景色？

<DataGrid>
    <DataGrid.RowStyle>
        <Style TargetType="DataGridRow">
            <Setter Property="Background" Value="LightBlue"/>
        </Style>
    </DataGrid.RowStyle>
</DataGrid>

private void dataGridView1_RowPrePaint(object sender, DataGridViewRowPrePaintEventArgs e)
{
    dataGridView1.Rows[e.RowIndex].DefaultCellStyle.BackColor = Color.LightBlue;
}