GroupStyle Property

ItemsControl.GroupStyle Property

 

Gets a collection of GroupStyle objects that define the appearance of each level of groups.

Namespace:   System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)

Public ReadOnly Property GroupStyle As ObservableCollection(Of GroupStyle)

Property Value

Type: System.Collections.ObjectModel.ObservableCollection(Of GroupStyle)

A collection of GroupStyle objects that define the appearance of each level of groups.

The entry at index 0 describes the top-level groups, the entry at index 1 describes the next level, and so on. If there are more levels of grouping than entries in the collection, the last entry is used for the extra levels.

<object>
  <object.GroupStyle>
    OneOrMoreGroupStyleObjects
  </object.GroupStyle>
</object>

OneOrMoreGroupStyleObjects

One or more GroupStyle objects.

The following examples show an ItemsControl that is bound to an XmlDataProvider and the code-behind content that contains the logic to add and remove grouping. When the check box is checked, the content of the ItemsControl is grouped by the Type attribute.

Each group is of type CollectionViewGroup. The GroupStyle HeaderTemplate is specified so that it appears as a TextBlock that displays the Name of each the group. In this case, the Name is either Work or Home.

<Window x:Class="GroupingSample.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Grouping Sample"
    Width="220" Height="550">
  <StackPanel>

    <StackPanel.Resources>
      <XmlDataProvider x:Key="myTasks" XPath="Tasks/Task">
        <x:XData>
          <Tasks xmlns="">
            <Task Name="Groceries" Priority="2" Type="Home">
              <Description>Pick up Groceries and Detergent</Description>
            </Task>
            <Task Name="Laundry" Priority="2" Type="Home">
              <Description>Do Laundry</Description>
            </Task>
            <Task Name="Email" Priority="1" Type="Work">
              <Description>Email Clients</Description>
            </Task>
            <Task Name="Clean" Priority="3" Type="Work">
              <Description>Clean my office</Description>
            </Task>
            <Task Name="Dinner" Priority="1" Type="Home">
              <Description>Get ready for family reunion</Description>
            </Task>
            <Task Name="Proposals" Priority="2" Type="Work">
              <Description>Review new budget proposals</Description>
            </Task>
          </Tasks>
        </x:XData>
      </XmlDataProvider>
    </StackPanel.Resources>

    <TextBlock Margin="12,5,5,0" FontSize="20" Text="My Task List"/>
    <CheckBox Margin="10,5,5,10" Checked="AddGrouping"
              Unchecked="RemoveGrouping">Group by task type</CheckBox>
    <ItemsControl Margin="10" Name="myItemsControl"
                  ItemsSource="{Binding Source={StaticResource myTasks}}">
      <ItemsControl.ItemTemplate>
        <DataTemplate>
          <DataTemplate.Resources>
            <Style TargetType="TextBlock">
              <Setter Property="FontSize" Value="18"/>
              <Setter Property="HorizontalAlignment" Value="Center"/>
            </Style>
          </DataTemplate.Resources>
          <Grid>
            <Ellipse Fill="Silver"/>
            <StackPanel>
              <TextBlock Margin="3,3,3,0"
                         Text="{Binding XPath=@Name}"/>
              <TextBlock Margin="3,0,3,7"
                         Text="{Binding XPath=@Priority}"/>
            </StackPanel>
          </Grid>
        </DataTemplate>
      </ItemsControl.ItemTemplate>
      <ItemsControl.ItemContainerStyle>
        <Style>
          <Setter Property="Control.Width" Value="100"/>
          <Setter Property="Control.Margin" Value="5"/>
        </Style>
      </ItemsControl.ItemContainerStyle>
      <ItemsControl.GroupStyle>
        <GroupStyle>
          <GroupStyle.HeaderTemplate>
            <DataTemplate>
              <TextBlock FontWeight="Bold" FontSize="15"
                         Text="{Binding Path=Name}"/>
            </DataTemplate>
          </GroupStyle.HeaderTemplate>
        </GroupStyle>
      </ItemsControl.GroupStyle>
    </ItemsControl>
  </StackPanel>
</Window>

Imports System
Imports System.Windows
Imports System.Windows.Data

Namespace GroupingSample
	Partial Public Class Window1
		Inherits System.Windows.Window

		Public Sub New()
			InitializeComponent()
		End Sub

		Private myView As CollectionView
		Private Sub AddGrouping(ByVal sender As Object, ByVal e As RoutedEventArgs)
			myView = CType(CollectionViewSource.GetDefaultView(myItemsControl.ItemsSource), CollectionView)
			If myView.CanGroup = True Then
				Dim groupDescription As New PropertyGroupDescription("@Type")
				myView.GroupDescriptions.Add(groupDescription)
			Else
				Return
			End If
		End Sub

		Private Sub RemoveGrouping(ByVal sender As Object, ByVal e As RoutedEventArgs)
			myView = CType(CollectionViewSource.GetDefaultView(myItemsControl.ItemsSource), CollectionView)
			myView.GroupDescriptions.Clear()
		End Sub
	End Class
End Namespace

.NET Framework
Available since 3.0
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