WPF Datatrigger for DataGrid only changing the entire row

I've got a DataGrid with a DataTrigger setup, so when it's value is "UP" I'd like the trigger to only change the background in the 'directionColumn' datagridcolumn only.

What I've got so far updates the entire row. I also tried placing 'targetname' in the setter element but that just gives an error. Please help.

XAML:

<DataGrid AutoGenerateColumns="False" ItemsSource="{Binding}" Name="summaryReportDataGridDATE" RowDetailsVisibilityMode="VisibleWhenSel开发者_如何学Cected" Width="330">
    <DataGrid.CellStyle>
        <Style TargetType="DataGridCell">
            <Style.Triggers>
                <DataTrigger Binding="{Binding Path=Direction}" Value="UP">
                    <Setter>
                        <Setter.Property>Background</Setter.Property>
                        <Setter.Value>Red</Setter.Value>
                    <!--<Setter Property="Background" Value="Red" TargetName="directionColumn"/>-->
                    </Setter>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DataGrid.CellStyle>
    <DataGrid.Columns>
        <!--<DataGridTemplateColumn x:Name="dateColumn" Header="Date" Width="100" CanUserReorder="False" CanUserSort="False" FontFamily="Arial Rounded MT" >
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <DatePicker SelectedDate="{Binding Path=Date, Mode=OneWay}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>-->

        <DataGridTextColumn x:Name="dateColumn" Binding="{Binding Path=Date, StringFormat={}{0:dd/MM/yyyy}}" Header="Date"  Width="80" CanUserReorder="False" CanUserSort="False" FontFamily="Arial Rounded MT"/>
        <DataGridTextColumn x:Name="closeColumn" Binding="{Binding Path=ClosingPrice}" Header="ClosingPrice" Width="80" CanUserReorder="False" CanUserSort="False" FontFamily="Arial Rounded MT" />
        <DataGridTextColumn x:Name="directionColumn" Binding="{Binding Path=Direction}" Header="Direction"  Width="80" CanUserReorder="False" CanUserSort="False" FontFamily="Arial Rounded MT" />
        <DataGridTextColumn x:Name="resultColumn" Binding="{Binding Path=Result}" Header="Result"  Width="80" CanUserReorder="False" CanUserSort="False" FontFamily="Arial Rounded MT"  />
    </DataGrid.Columns>
</DataGrid>

How about a TemplateColumn instead of custom cell style:

    <DataGrid AutoGenerateColumns="False" ItemsSource="{Binding}" Name="summaryReportDataGridDATE" RowDetailsVisibilityMode="VisibleWhenSelected" Width="330">                       
        <DataGrid.Columns>
            <DataGridTextColumn x:Name="dateColumn" Binding="{Binding Path=Date, StringFormat={}{0:dd/MM/yyyy}}" Header="Date"  Width="80" CanUserReorder="False" CanUserSort="False" FontFamily="Arial Rounded MT"/>
            <DataGridTextColumn x:Name="closeColumn" Binding="{Binding Path=ClosingPrice}" Header="ClosingPrice" Width="80" CanUserReorder="False" CanUserSort="False" FontFamily="Arial Rounded MT" />
            <DataGridTemplateColumn x:Name="directionColumn" Header="Direction"  Width="80" CanUserReorder="False" CanUserSort="False" >
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <TextBlock x:Name="directionColumnTextBlock" Text="{Binding Path=Direction}" Width="80" FontFamily="Arial Rounded MT"/>
                        <DataTemplate.Triggers>
                            <DataTrigger Binding="{Binding Path=Direction}" Value="UP">
                                <Setter TargetName="directionColumnTextBlock" Property="Background" Value="Red" />
                            </DataTrigger>
                        </DataTemplate.Triggers>
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
            </DataGridTemplateColumn>                                                                              
            <DataGridTextColumn x:Name="resultColumn" Binding="{Binding Path=Result}" Header="Result"  Width="80" CanUserReorder="False" CanUserSort="False" FontFamily="Arial Rounded MT"  />
        </DataGrid.Columns>
    </DataGrid>