How to set DataGridCheckBoxColumn checkbox background color?

I have a DataGridCheckBoxColumn that I want to set the background color of the checkbox to indicate that it is readonly. I have figured out how to set the entire cell background color using a CellStyle tag, however, I can't figure out what I need to do to target the checkbox's background color, and not the entire data cell.

Below is what I have, which sets the color of the DataGridCell, not the checkbox. I seem to be getting exception if I have anything as the TargeType besides DataGridCell.

<DataGridCheckBoxColumn Header="Processed" Binding="{Binding Path=IsProcessingComplete, Mode=OneWay}" Width="70" IsReadOnly="True">
    <DataGridCheckBoxColumn.CellStyle>
        <Style TargetType="DataGridCell">
            <Setter Property="Background" Value="Gray"/>
       开发者_JAVA百科 </Style>
    </DataGridCheckBoxColumn.CellStyle>
</DataGridCheckBoxColumn>

Try to use DataGridTemplateColumn. I think that it would be easier than DataGridCheckBoxColumn to set the `Background'.

<DataGrid ItemsSource="{Binding}" >
    <DataGrid.Columns>
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <CheckBox Background="Red"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>