Custom Group-configuration Selectors

In addition to the built-in LevelGroupConfigurationSelector and FieldNameGroupConfigurationSelector group-configuration selectors, which can be used to select the appropriate configuration for a group based on its level or field name, custom group-configuration selectors can also be created and used.

Custom group-configuration selectors (with or without corresponding selector items) can be created by deriving from the GroupConfigurationSelector class and overriding the SelectGroupConfiguration method to return the appropriate group configuration based on the desired criteria (see Example 1). If a selector does not have a group configuration that corresponds to the specified information it should either call the base implementation or return null (Nothing in VisualBasic).

Examples

All examples in this topic assume that the grid is bound to the Orders table of the Northwind database, unless stated otherwise.

Example 1: Creating a group-configuration selector

The following example demonstrates how to create a custom group-configuration selector that will return the appropriate group configuration depending on the number of items in a group. The implementation of the ItemCountGroupConfigurationSelector is provided below.

XAML
C#
VB.NET

<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid">
  <Grid.Resources>
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                      Source="{Binding Source={x:Static Application.Current},
                                                        Path=Orders}">
      <xcdg:DataGridCollectionViewSource.GroupDescriptions>             
        <xcdg:DataGridGroupDescription PropertyName="ShipCity" />
      </xcdg:DataGridCollectionViewSource.GroupDescriptions>
    </xcdg:DataGridCollectionViewSource>
  </Grid.Resources>
  <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}">
    <xcdg:DataGridControl.GroupConfigurationSelector>
      <local:ItemCountGroupConfigurationSelector MinItemCount="10" />
    </xcdg:DataGridControl.GroupConfigurationSelector>
  </xcdg:DataGridControl>
</Grid>

DataGridCollectionView collectionView = new DataGridCollectionView( Orders );     
collectionView.GroupDescriptions.Add( new DataGridGroupDescription( "ShipCity" ) );
dataGridControl.GroupConfigurationSelector = new ItemCountGroupConfigurationSelector( 10 );
dataGridControl.ItemsSource = collectionView;

Dim collectionView As New DataGridCollectionView( Orders )
collectionView.GroupDescriptions.Add( New DataGridGroupDescription( "ShipCity" ) )
dataGridControl.GroupConfigurationSelector = New ItemCountGroupConfigurationSelector( 10 )
dataGridControl.ItemsSource = collectionView

The following code provides the implementation of the ItemCountGroupConfigurationSelector.

C#
VB.NET

 public class ItemCountGroupConfigurationSelector : GroupConfigurationSelector
{
  public ItemCountGroupConfigurationSelector()
  {
  }
  public ItemCountGroupConfigurationSelector( int minItemCount )
  :base()
  {
    this.MinItemCount = minItemCount;
  }
public override GroupConfiguration SelectGroupConfiguration( int groupLevel,
                System.Windows.Data.CollectionViewGroup collectionViewGroup,
                System.ComponentModel.GroupDescription groupDescription )
{
  if( collectionViewGroup == null )
    return base.SelectGroupConfiguration( groupLevel, collectionViewGroup, groupDescription );
  GroupConfiguration groupConfiguration = new GroupConfiguration();
  Style style = new Style( typeof( Xceed.Wpf.DataGrid.DataRow ) );
  if( collectionViewGroup.ItemCount <= m_minItemCount ) // red
  {
    style.Setters.Add( new Setter( Xceed.Wpf.DataGrid.DataRow.BackgroundProperty, Brushes.Red ) );      
  }
  else // green
  {
    style.Setters.Add( new Setter( Xceed.Wpf.DataGrid.DataRow.BackgroundProperty, Brushes.LightGreen ) );      
  }
  groupConfiguration.ItemContainerStyle = style;
  return groupConfiguration;
}
  private int m_minItemCount = 0;
  public int MinItemCount
  {
    get
    {
      return m_minItemCount;
    }
    set
    {
      if( value != m_minItemCount )
        m_minItemCount = value;
    }
  }
}

  Public Class ItemCountGroupConfigurationSelector
         Inherits GroupConfigurationSelector
    Public Sub New
    End Sub
    Public Sub New( minItemCount As Integer )
      Me.MinItemCount = minItemCount
    End Sub
    Public Overrides Function SelectGroupConfiguration( ByVal groupLevel As Integer, _
                    ByVal collectionViewGroup As System.Windows.Data.CollectionViewGroup, _
                    ByVal groupDescription As System.ComponentModel.GroupDescription ) As GroupConfiguration
      If collectionViewGroup Is Nothing Then
        Return MyBase.SelectGroupConfiguration( groupLevel, collectionViewGroup, groupDescription )
      End If
      Dim groupConfiguration As New GroupConfiguration()
      Dim style As New Style( GetType( Xceed.Wpf.DataGrid.DataRow ) )
      If collectionViewGroup.ItemCount <= m_minItemCount Then ' red
        style.Setters.Add( New Setter( Xceed.Wpf.DataGrid.DataRow.BackgroundProperty, Brushes.Red ) )
      Else ' green
        style.Setters.Add( New Setter( Xceed.Wpf.DataGrid.DataRow.BackgroundProperty, Brushes.LightGreen ) )
      End If
      groupConfiguration.ItemContainerStyle = style
      Return groupConfiguration
    End Function
    Private m_minItemCount As Integer = 0
    Public Property MinItemCount As Integer
      Get
        Return m_minItemCount
      End Get
      Set
        m_minItemCount = value
    End Property
  End Class

Examples​

Examples