Compare two databound cells in wpf datagrid

Question

I'm looking to compare databound cells in the same row of data to each other and highlight in red if they are different the cells that they are in.

If I statically provide a value for the conversion the cell is highlighted correctly, but I cant for the life of me figure out how to compare two cells of data in the same row. The below doesn't work as the Value parameter wont accept a databound item. This is my first foray into WPF so please be kind ;)

Can anybody advise how I can do a comparison of two items on the same row of data?

<DataGridTextColumn x:Name="oldContainerNumberColumn" Binding="{Binding OldContainerNumber}" Header="Old Container Number" IsReadOnly="True" Width="SizeToHeader">
                    <DataGridTextColumn.CellStyle>
                        <Style TargetType="DataGridCell">
                            <Style.Triggers>
                                <DataTrigger Binding="{Binding OldContainerNumber,Converter={StaticResource StringComparisonConverter},ConverterParameter={Binding NewContainerNumber}}" Value="True">
                                    <Setter Property="Background" Value="Red" />
                                    <Setter Property="Foreground" Value="White" />
                                </DataTrigger>
                            </Style.Triggers>
                        </Style>
                    </DataGridTextColumn.CellStyle>

                </DataGridTextColumn>

Answer 1

You can't bind to ConverterParameter because it's not a DependencyProperty.

You could use a MultiBinding within the DataTrigger:

<DataTrigger Value="True">
    <DataTrigger.Binding>
        <MultiBinding Converter="{StaticResource StringComparisonConverter}">
            <Binding Path="OldContainerNumber" />
            <Binding Path="NewContainerNumber" />
        </MultiBinding>
    </DataTrigger.Binding>
    <Setter Property="Background" Value="Red" />
    <Setter Property="Foreground" Value="White" />
</DataTrigger>

Of course you have to change your StringComparisonConverter to an IMultiValueConverter.

---

I think simpler solution would be to add a new property doing the comparison. Something like in this sample:

class YourClass
{
    public int OldContainerNumber { get; set; }
    public int NewContainerNumber { get; set; }

    public bool IsEqual
    {
        get { return OldContainerNumber == NewContainerNumber; }
    }
}

No need for a Converter:

<Style TargetType="DataGridCell">
    <Style.Triggers>
        <DataTrigger Binding="{Binding IsEqual}" Value="True">
            <Setter Property="Background" Value="Red" />
            <Setter Property="Foreground" Value="White" />
        </DataTrigger>
    </Style.Triggers>
</Style>