WPF pass object to datagrid's converter and change color of one cell

Question

currently I am trying to make converter, that changes background color of one cell in DataGrid's row. Each row represents one CustomTask object. Now my converter changes backroung of entire row. It's not what I want, I need to change background of only one chosen cell.

My xaml:

<DataGrid x:Name="customTasksDataGrid" Margin="10,10,10,38" Grid.Column="1" IsReadOnly="True" AutoGenerateColumns="False">
    <DataGrid.RowStyle>
        <Style TargetType="DataGridRow">
            <Setter Property="Background" Value="{Binding Path=., Converter={StaticResource converter}}" />
        </Style>
    </DataGrid.RowStyle>
    <DataGrid.Columns>
        <DataGridTextColumn Header="ID" Binding="{Binding ID}"/>
        <DataGridTextColumn Header="Foo" Binding="{Binding Foo}"/>
        <DataGridTextColumn Header="Bar" Binding="{Binding Bar}"/>
        ...
    </DataGrid.Columns>
</DataGrid>

My converter:

[ValueConversion(typeof(DataRowView), typeof(Brush))]
public class DateToBrushConverter : IValueConverter
{

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value == null)
            return null;
        CustomTask t = (CustomTask)value;
        return new SolidColorBrush(Color.FromArgb(255,0,0,120));
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Changing color of entire row roks perfectly now. How to change for example Bar cell background color depending on Foo value?

Answer 1

You need to specify the TextColumn style individually, not the entire row.

<DataGrid x:Name="customTasksDataGrid" Margin="10,10,10,38" Grid.Column="1" IsReadOnly="True" AutoGenerateColumns="False">
    <DataGrid.Columns>
        <DataGridTextColumn Header="ID" Binding="{Binding ID}"/>
        <DataGridTextColumn Header="Foo" Binding="{Binding Foo}"/>
        <DataGridTextColumn Header="Bar" Binding="{Binding Bar}">
            <DataGridTextColumn.ElementStyle>
                <Style TargetType="{x:Type TextBlock}">
                    <Setter Property="Background" Value="{Binding Path=., Converter={StaticResource converter}}"/>
                </Style>
            </DataGridTextColumn.ElementStyle>
        </DataGridTextColumn>
    </DataGrid.Columns>
</DataGrid>