WPF DataGrid selected row style

Use CellStyle and RowStyle on DataGrid. DataGridCell and DataGridRow both have IsSelected property that can be used in a Trigger to find out if they are selected.

Something like following should do the trick:

<DataGrid.CellStyle>
    <Style TargetType="DataGridCell">
        <Style.Triggers>
            <Trigger Property="IsSelected"
                        Value="True">
                <Setter Property="Background"
                        Value="White" />
                <Setter Property="Foreground"
                        Value="Black" />
            </Trigger>
        </Style.Triggers>
    </Style>
</DataGrid.CellStyle>
<DataGrid.RowStyle>
    <Style TargetType="DataGridRow">
        <Style.Triggers>
            <Trigger Property="IsSelected"
                        Value="True">
                <Setter Property="BorderBrush"
                        Value="Blue" />
                <Setter Property="BorderThickness"
                        Value="2" />
            </Trigger>
        </Style.Triggers>
    </Style>
</DataGrid.RowStyle>

Just play around until you get it right.