unset style in trigger

Question

i have styles defined in general for this control, now i wand define a style for a given control.

then i have DataTrigger, if it meet the condition i wont to unset the style defined on the control and go back to the general style i have defined.

i don't want to set hardcoded values as in sample bellow, but go back to the general style.

any suggestions how to do it?

here a sample of my code:

                    <DataGrid.Style>
                    <Style TargetType="DataGridRow">
                        <Setter Property="Foreground" Value="Gray"/>
                        <Setter Property="FontWeight" Value="Light"/>
                        <Setter Property="FontStyle" Value="Italic" />
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding VoidedOn}" Value="{x:Null}">

                                    <Setter Property="Foreground" Value="?"/>
                                <Setter Property="FontWeight" Value="?"/>
                                <Setter Property="FontStyle" Value="?" />
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </DataGrid.Style>

any suggestions how to do it? thanks

Answer 1

There is no ClearValue in xaml unfortunately. Of course you could create an attached behavior especially for that case calling ClearValue for these properties, but this would be a lot of work for very little.

The easiest and imho clearest solution is to create 2 resources for FontStyle and use them in the correct setter.

<FontStyle x:Key="voidedOnStyle">Italic</FontStyle>
<FontStyle x:Key="normalStyle">Normal</FontStyle>

<Setter Property="FontStyle" Value="{StaticResource voidedOnStyle}" />
<Style.Triggers>
    <DataTrigger Binding="{Binding VoidedOn}" Value="{x:Null}">
        <Setter Property="FontStyle" Value="{StaticResource normalStyle}" />
    </DataTrigger>
</Style.Triggers>