Change HorizontalGridLinesBrush only for selected Row

Question

In a WPF ´DataGrid´ the Color of the Horizontal Grid Line can be modified by the HorizontalGridLinesBrush Property.

Some Items have a boolean Property set to true so I want to highlight them with the Horizontal Grid Line Brush set to another Color.

Is it possible to change the Color of the Horizontal Grid Line only for cetain Rows?

Answer 1

DataGrid.HorizontalGridLinesBrush is set per DataGrid so you cannot change it per row but you could replace default horizontal line behaviour by disabling horizontal grid lines and creating custom DataGridRow style

<DataGrid ... GridLinesVisibility="Vertical">
    <DataGrid.RowStyle>
        <Style TargetType="{x:Type DataGridRow}">
            <Setter Property="BorderThickness" Value="0,0,0,1"/>
            <Setter Property="BorderBrush" Value="Black"/>
            <Style.Triggers>

                <!-- this will trigger when row is selected -->
                <Trigger Property="IsSelected" Value="True">                        
                    <Setter Property="BorderBrush" Value="Red"/>
                </Trigger>

                <!-- this will trigger when Highlight property of the view model is true -->
                <DataTrigger Binding="{Binding Highlight}" Value="True">
                    <Setter Property="BorderBrush" Value="Green"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </DataGrid.RowStyle>
</DataGrid>