How to use row index as a condition in a multitrigger for a DataGridCell style in WPF XAML?

Question

I want to know how to use the row index as a condition in the same way the column index is used in the code below:

<Style x:Key="DefaultDataGridCell" TargetType="{x:Type DataGridCell}">
<Setter Property="IsTabStop" Value="False" />
<Style.Triggers>
    <MultiDataTrigger>
        <MultiDataTrigger.Conditions>
            <Condition Binding="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=Column.DisplayIndex}" Value="0" />
        </MultiDataTrigger.Conditions>
        <Setter Property="IsTabStop" Value="True" />
    </MultiDataTrigger>
</Style.Triggers>

In this example the entire first column of the DataGrid is tabstop but I only need the first cell of the DataGrid to be tabstop. How can I do it?

Answer 1

There is no property that you can bind to that returns the index of the row but the DataGridRow class has a GetIndex() method that you could call in a converter class:

namespace WpfApplication1
{

    public class MyConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return (value as DataGridRow).GetIndex();
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}

---

<Style x:Key="DefaultDataGridCell" TargetType="{x:Type DataGridCell}"
               xmlns:local="clr-namespace:WpfApplication1">
    <Style.Resources>
        <local:MyConverter x:Key="conv" />
    </Style.Resources>
    <Setter Property="IsTabStop" Value="False" />
    <Style.Triggers>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding RelativeSource={x:Static RelativeSource.Self}, Path=Column.DisplayIndex}" Value="0" />
                <Condition Binding="{Binding RelativeSource={RelativeSource AncestorType=DataGridRow}, Converter={StaticResource conv}}" Value="0" />
            </MultiDataTrigger.Conditions>
            <Setter Property="IsTabStop" Value="True" />
        </MultiDataTrigger>
    </Style.Triggers>
</Style>

You cannot bind directly to a method though so you will have to use a converter.