Grouping Data Items

The following page provides a list of examples that demonstrate how to group data items.

tip

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

Grouping data items

The following example demonstrates how to group the data items by the ShipCountry and ShipCity columns.

XAML

  <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="ShipCountry"/>
        <xcdg:DataGridGroupDescription PropertyName="ShipCity"/>
      </xcdg:DataGridCollectionViewSource.GroupDescriptions>
      </xcdg:DataGridCollectionViewSource>
    </Grid.Resources>
    
    <xcdg:DataGridControl x:Name="OrdersGrid"
                          ItemsSource="{Binding Source={StaticResource cvs_orders}}">     
    </xcdg:DataGridControl>
  </Grid>

C#

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

VB.NET

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

Preventing group and sorting

The following example demonstrates how to bind a grid to the Orders table and prevent columns from being sorted and reordered and groups from being created or removed. By default, the ShipCountry and ShipCity columns will be sorted, grouped, and fixed.

<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
      xmlns:d="clr-namespace:System.Windows.Data;assembly=PresentationFramework"
      xmlns:scm="clr-namespace:System.ComponentModel;assembly=WindowsBase">
  <Grid.Resources>
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                    Source="{Binding Source={x:Static Application.Current},
                                                      Path=Orders}">
      <xcdg:DataGridCollectionViewSource.SortDescriptions>
        <scm:SortDescription PropertyName="ShipCountry" Direction="Ascending"/>
        <scm:SortDescription PropertyName="ShipCity" Direction="Ascending"/>
      </xcdg:DataGridCollectionViewSource.SortDescriptions>
      <xcdg:DataGridCollectionViewSource.GroupDescriptions>
        <xcdg:DataGridGroupDescription PropertyName="ShipCountry"/>
        <xcdg:DataGridGroupDescription PropertyName="ShipCity"/>
      </xcdg:DataGridCollectionViewSource.GroupDescriptions>
    </xcdg:DataGridCollectionViewSource>
  </Grid.Resources>
  <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}">      
    <xcdg:DataGridControl.Columns>
      <xcdg:Column FieldName="ShipCountry" VisiblePosition="0"/>
      <xcdg:Column FieldName="ShipCity" VisiblePosition="1"/>
    </xcdg:DataGridControl.Columns>
    <xcdg:DataGridControl.View>
      <xcdg:TableView FixedColumnCount="2" UseDefaultHeadersFooters="False">
        <xcdg:TableView.FixedHeaders>
          <DataTemplate>
            <xcdg:GroupByControl AllowSort="False" AllowGroupingModification="False"/>
          </DataTemplate>
          <DataTemplate>
            <xcdg:ColumnManagerRow AllowSort="False" AllowColumnReorder="False"/>
          </DataTemplate>
        </xcdg:TableView.FixedHeaders>
      </xcdg:TableView>
    </xcdg:DataGridControl.View>
  </xcdg:DataGridControl>
</Grid>

Defining a default group configuration

The following example demonstrates how to provide a default group configuration.

<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="ShipCountry"/>
          <xcdg:DataGridGroupDescription PropertyName="ShipCity"/>
        </xcdg:DataGridCollectionViewSource.GroupDescriptions>
      </xcdg:DataGridCollectionViewSource>
    </Grid.Resources>
    <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}">
      <xcdg:DataGridControl.DefaultGroupConfiguration>
        <xcdg:GroupConfiguration>
          <xcdg:GroupConfiguration.Footers>
            <DataTemplate>
              <xcdg:InsertionRow/>
            </DataTemplate>
          </xcdg:GroupConfiguration.Footers>
        </xcdg:GroupConfiguration>
      </xcdg:DataGridControl.DefaultGroupConfiguration>      
    </xcdg:DataGridControl> 
  </Grid>

Programmatically toggling group expansion

The following example demonstrates how to handle the PreviewMouseLeftButtonDown event on the GroupHeaderControl objects contained in the headers of the child groups to toggle the expansion state of child groups using the ToggleGroupExpansion method. The group whose state is to be toggled will be retrieved using the GetParentGroupFromItem method.

XAML

  <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="ShipCountry"/>
          <xcdg:DataGridGroupDescription PropertyName="ShipCity"/>
        </xcdg:DataGridCollectionViewSource.GroupDescriptions>
      </xcdg:DataGridCollectionViewSource>
      <Style TargetType="{x:Type xcdg:GroupHeaderControl}">
        <EventSetter Event="PreviewMouseLeftButtonDown"
                    Handler="HeaderDown"/>
      </Style>  
  </Grid.Resources>
    <xcdg:DataGridControl x:Name="OrdersGrid"
                          ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>
  </Grid>

C#

  private void HeaderDown( object sender, MouseEventArgs e )
  {
    GroupHeaderControl headerControl = sender as GroupHeaderControl;
    if( headerControl == null )
      return;
    DataGridContext context = DataGridControl.GetDataGridContext( headerControl );
    object item = context.GetItemFromContainer( headerControl );
    if( item != null )
    {
      CollectionViewGroup group = context.GetParentGroupFromItem( item );
      if( group != null )
      {
        context.ToggleGroupExpansion( group );
      }
    }
  }

VB.NET

  Private Sub HeaderDown( ByVal sender As Object, ByVal e As MouseButtonEventArgs )
    Dim headerControl As GroupHeaderControl = TryCast( sender, GroupHeaderControl );
    If headerControl Is Nothing Then
      Return
    End If
    Dim context As DataGridContext = DataGridControl.GetDataGridContext( headerControl )
    Dim item As Object = context.GetItemFromContainer( headerControl ) )
    If Not item Is Nothing Then
      Dim group As CollectionViewGroup = context.GetParentGroupFromItem( item )
      If Not group Is Nothing
        context.ToggleGroupExpansion( group )
      End If
    End If
  End Sub

Custom grouping

This example demonstrates how to create a custom group description by deriving from the DataGridGroupDescription class and overriding the GroupNameFromItem method. The custom group description will group items according to the first letter in the value received as a parameter. The example results in the group being present at initial loading; also, when removing and re-adding the group, the custom group description is not triggered. See below for an alternative approach to avoid this.

The implementation for the custom sort comparer assigned to the group description's SortComparer property is provided below.

C#

  using System;
  using System.Collections.Generic;
  using System.Text;
  using Xceed.Wpf.DataGrid;
  using System.Collections;
  namespace Xceed.Wpf.Documentation
  {
    public class AlphabeticalGroupDescription : DataGridGroupDescription
    {
      public AlphabeticalGroupDescription()
        : base()
      {
      }
      public AlphabeticalGroupDescription( string propertyName )
        : base( propertyName )
      {
      }
    
      public override object GroupNameFromItem( object item, int level,
                                                System.Globalization.CultureInfo culture )
      {
        object value = base.GroupNameFromItem( item, level, culture );
        try
        {
          string content = Convert.ToString( value );
          value = content.ToUpper().Substring( 0, 1 );
        }
        catch( InvalidCastException )
        {
        }
        return value;
      }
    }
  }

VB.NET

  Imports System
  Imports System.Collections.Generic
  Imports System.Text
  Imports Xceed.Wpf.DataGrid
  Imports System.Collections
  Imports System.Globalization;
  Namespace Xceed.Wpf.Documentation
    Public Class AlphabeticalGroupDescription
          Inherits DataGridGroupDescription
      Public Sub New()
        MyBase.New()
      End Sub
      Public Sub New(ByVal propertyName As String)
      MyBase.New(propertyName)
      End Sub
      Public Overrides Function GroupNameFromItem(ByVal item As Object, _
                                                  ByVal level As Integer, _
                                                  ByVal culture As CultureInfo) As Object
        Dim value As Object = MyBase.GroupNameFromItem(item, level, culture)
        Try
          Dim content As String = Convert.ToString(value)
          value = content.ToUpper().Substring(0, 1)
        Catch e1 As InvalidCastException
        End Try
        Return value
      End Function
    End Class
  End Namespace

The following code demonstrates how to use the custom group description by adding it to the DataGridCollectionViewSource's GroupDescriptions property.

XAML

  <Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
        xmlns:local="clr-namespace:Xceed.Wpf.Documentation">
    <Grid.Resources>     
      <local:ConsonantVowelComparer x:Key="consonantVowelComparer"/>
      <xcdg:DataGridCollectionViewSource x:Key="cvs_orders"
                                        Source="{Binding
                                                  Source={x:Static Application.Current},
                                                  Path=Orders}">
      <xcdg:DataGridCollectionViewSource.GroupDescriptions>
        <local:AlphabeticalGroupDescription PropertyName="ShipCountry"
                                  SortComparer="{StaticResource consonantVowelComparer}"/>
      </xcdg:DataGridCollectionViewSource.GroupDescriptions>
      </xcdg:DataGridCollectionViewSource>
    </Grid.Resources>
    <xcdg:DataGridControl x:Name="OrdersGrid"
                          ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>
  </Grid>

C#

  DataGridCollectionView collectionView = new DataGridCollectionView( Orders );
  AlphabeticalGroupDescription groupDescription = new AlphabeticalGroupDescription( "ShipCountry" );
  groupDescription.SortComparer = new ConsonantVowelComparer();
  collectionView.GroupDescriptions.Add( groupDescription );
  dataGridControl.ItemsSource = collectionView;

VB.NET

  Dim collectionView As New DataGridCollectionView( Orders )
  Dim groupDescription As New AlphabeticalGroupDescription( "ShipCountry" )
  groupDescription.SortComparer = New ConsonantVowelComparer()
  collectionView.GroupDescriptions.Add( groupDescription )
  dataGridControl.ItemsSource = collectionView

The following code provides the implementation for the custom sort comparer that is used to sort, by vowels then consonants, the group descriptions create above.

XAML

  <Window.Resources>
      <local:DateGroupDescription x:Key="myDateGroupDescription"
                                  PropertyName="DateTimeFieldName" />
  </Window.Resources>

  [...]

  <xcdg:DataGridControl.Columns>
    <xcdg:Column FieldName="DateTimeFieldName"
                GroupDescription="{StaticResource myDateGroupDescription}" />
  </xcdg:DataGridControl.Columns>

C#

  using System;
  using System.Collections.Generic;
  using System.Text;
  using System.Collections;
  namespace Xceed.Wpf.Documentation
  {
    public class ConsonantVowelComparer : IComparer
    {
      public ConsonantVowelComparer()
      {
      }
      public int Compare( object x, object y )
      {
        if( ( x is string ) && ( y is string ) )
        {
          string xString = x.ToString().ToLowerInvariant();
          string yString = y.ToString().ToLowerInvariant();
          bool isXVowel = m_vowels.Contains( xString );
          bool isYVowel = m_vowels.Contains( yString );
          if( isXVowel ^ isYVowel )
            return isXVowel ? -1 : 1;
          return String.Compare( xString, yString );      
        }
        throw new ArgumentException();
      }
      private const string m_vowels = "aeiouy";
    }
  }

VB.NET

  Imports System
  Imports System.Collections.Generic
  Imports System.Text
  Imports System.Collections
  Namespace Xceed.Wpf.Documentation
    Public Class ConsonantVowelComparer
      Implements IComparer
      Public Sub New()
      End Sub

      Public Function Compare(ByVal x As Object, _
                              ByVal y As Object) As Integer Implements IComparer.Compare
        If (TypeOf x Is String) AndAlso (TypeOf y Is String) Then
          Dim xString As String = x.ToString().ToLowerInvariant()
          Dim yString As String = y.ToString().ToLowerInvariant()
          Dim isXVowel As Boolean = m_vowels.Contains(xString)
          Dim isYVowel As Boolean = m_vowels.Contains(yString)
          If isXVowel Xor isYVowel Then
            If isXVowel Then
              Return -1
            Else
              Return 1
            End If
          End If
          Return String.Compare(xString, yString)
        End If
        Throw New ArgumentException()
      End Function
      Private Const m_vowels As String = "aeiouy"
    End Class
  End Namespace

Changing the group-header text

The following example demonstrates how to change the information displayed in each GroupHeaderControl by creating an implicit DataTemplate targeting the Group data type.

<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="ShipCountry"/>
      </xcdg:DataGridCollectionViewSource.GroupDescriptions>
    </xcdg:DataGridCollectionViewSource>
    <DataTemplate DataType="{x:Type xcdg:Group}">
      <StackPanel Orientation="Horizontal">
        <TextBlock Text="The "/>
        <TextBlock Text="{Binding Value}"/>
        <TextBlock Text=" group contains "/>
        <TextBlock Text="{Binding Items.Count}"/>
        <TextBlock Text=" items."/>
      </StackPanel>
    </DataTemplate>
  </Grid.Resources>
  <xcdg:DataGridControl x:Name="OrdersGrid"
                        ItemsSource="{Binding Source={StaticResource cvs_orders}}"/>
</Grid>

Providing a group-configuration selector

The following example demonstrates how to provide a FieldNameGroupConfigurationSelector that will apply the defined group configuration to all groups that are created from the values of the column corresponding to the specified field name.

<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="ShipCountry" />
        <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>
      <xcdg:FieldNameGroupConfigurationSelector>
        <xcdg:FieldNameGroupConfigurationSelectorItem FieldName="ShipCity">
          <xcdg:FieldNameGroupConfigurationSelectorItem.GroupConfiguration>
            <xcdg:GroupConfiguration>
              <xcdg:GroupConfiguration.Footers>
                <DataTemplate>
                  <xcdg:InsertionRow />
                </DataTemplate>
              </xcdg:GroupConfiguration.Footers>
            </xcdg:GroupConfiguration>
          </xcdg:FieldNameGroupConfigurationSelectorItem.GroupConfiguration>                
        </xcdg:FieldNameGroupConfigurationSelectorItem>
      </xcdg:FieldNameGroupConfigurationSelector>
    </xcdg:DataGridControl.GroupConfigurationSelector>
  </xcdg:DataGridControl>
</Grid>

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

  <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>

C#

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

VB.NET

  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#

    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;
          }
        }
      }

VB.NET

    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