public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        var x = value;
        if (x.ToString().Contains("ночь"))
        {
            return System.Windows.Media.Brushes.LightBlue;
        }
        else if (x.ToString().Contains("день"))
        {
            return System.Windows.Media.Brushes.LightYellow;
        }
        else
        {
            return value;
        }
    }

<Style TargetType="DataGridCell">
                        <Setter Property="Background" Value="{Binding Content.Text,RelativeSource={RelativeSource Self}, Converter={StaticResource IsPivotalEntryToColorConverter}, Mode=OneWay}"/>
                        <Setter Property="Foreground" Value="Black"/>
                    </Style>

DataView buf = newDt.DefaultView;
        Schedule_table.ItemsSource = buf;