发送DataGrid ItemsSource作为converterParameter

Question

In WPF, I need to add border to a dataGridRow based on comparison with other rows in this data grid.

I can't alter the source items properties, so I would like to use a converter to set the style of rows that match a condition.

How can I pass current ObservableCollection that is used as DataGrid ItemsSource to a converter as a converterParameter?

<DataGrid ItemsSource="{Binding TableItems}" Name="TableDataGrid" AutoGenerateColumns="False" BorderThickness="0">
    <DataGrid.ItemContainerStyle>
        <Style TargetType="DataGridRow">
            <Setter Property="BorderBrush" Value="#FF9E9E9E"/>
            <Setter Property="BorderThickness" Value="{Binding Path=., Converter={StaticResource converter}, ConverterParameter= ??? }"/>
        </Style>
    </DataGrid.ItemContainerStyle>
    <DataGrid.Columns>
    ...
    </DataGrid.Columns>
</DataGrid>

From sample code above, I would like to pass TableItems as ConverterParameter.

Answer 1

Since you can't bind the ConverterParameter property of a Binding, you should use a MultiBinding and make your converter implement IMultiValueConverter .

<Setter Property="BorderThickness">
    <Setter.Value>
        <MultiBinding Converter="{StaticResource converter}">
            <Binding Path="."/>
            <Binding Path="DataContext.TableItems"
                     RelativeSource="{RelativeSource AncestorType=DataGrid}"/>
        </MultiBinding>
    </Setter.Value>
</Setter>

Answer 2

You can't bind anything to the ConverterParameter property since it is not a dependency property.

You could either use an IMultiValueConverter that takes several input values:

<DataGrid.ItemContainerStyle>
    <Style TargetType="DataGridRow">
        <Setter Property="BorderBrush" Value="#FF9E9E9E"/>
        <Setter Property="BorderThickness">
            <Setter.Value>
                <MultiBinding Converter="{StaticResource multiConverter}">
                    <Binding Path="." />
                    <Binding Path="DataContext.TableItems" RelativeSource="{RelativeSource AncestorType=DataGrid}" />
                </MultiBinding>
            </Setter.Value>
        </Setter>
    </Style>
</DataGrid.ItemContainerStyle>

Or you could add a depenendency property to your converter and bind this one to the ItemsSource collection of your DataGrid :

public class DataGridConverter : DependencyObject, IValueConverter
{
    public static readonly DependencyProperty SourceCollectionProperty =
         DependencyProperty.Register("SourceCollection", typeof(IEnumerable),
         typeof(DataGridConverter), new FrameworkPropertyMetadata(null));

    public IEnumerable SourceCollection
    {
        get { return (IEnumerable)GetValue(SourceCollectionProperty); }
        set { SetValue(SourceCollectionProperty, value); }
    }


    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value;
    }

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

---

<DataGrid ItemsSource="{Binding TableItems}" Name="TableDataGrid" AutoGenerateColumns="False" BorderThickness="0">
    <DataGrid.Resources>
        <local:DataGridConverter x:Key="converter" SourceCollection="{Binding Path=DataContext.TableItems, Source={x:Reference TableDataGrid}}" />
    </DataGrid.Resources>
    <DataGrid.ItemContainerStyle>
        <Style TargetType="DataGridRow">
            <Setter Property="BorderBrush" Value="#FF9E9E9E"/>
            <Setter Property="BorderThickness" Value="{Binding Path=., Converter={StaticResource converter}}"/>
        </Style>
    </DataGrid.ItemContainerStyle>
</DataGrid>