HierarchicalDataTemplate.ItemContainerStyleSelector HierarchicalDataTemplate.ItemContainerStyleSelector HierarchicalDataTemplate.ItemContainerStyleSelector HierarchicalDataTemplate.ItemContainerStyleSelector Property

Definition

Ruft eine benutzerdefinierte Formatauswahllogik für einen Stil ab, der auf alle Elementcontainer angewendet werden kann, oder legt diese fest.Gets or sets custom style-selection logic for a style that can be applied to each item container.

public:
 property System::Windows::Controls::StyleSelector ^ ItemContainerStyleSelector { System::Windows::Controls::StyleSelector ^ get(); void set(System::Windows::Controls::StyleSelector ^ value); };
public System.Windows.Controls.StyleSelector ItemContainerStyleSelector { get; set; }
member this.ItemContainerStyleSelector : System.Windows.Controls.StyleSelector with get, set
Public Property ItemContainerStyleSelector As StyleSelector

Eigenschaftswert

Ein StyleSelector, der den Stil auswählt, der als ItemContainerStyle verwendet werden soll.A StyleSelector that chooses which style to use as the ItemContainerStyle. Die Standardeinstellung ist null.The default is null.

Beispiele

Im folgenden Beispiel wird eine TreeView erstellt, die ItemContainerStyle den HierarchicalDataTemplate einer verwendet, um zwischen zwei Stilen TreeViewfür Elemente auf der zweiten Ebene des auszuwählen.The following example creates a TreeView that uses the ItemContainerStyle of a HierarchicalDataTemplate to choose between two styles for items in the second level of the TreeView.

<StackPanel Name="sp1" x:FieldModifier="public">
  <StackPanel.Resources>
    <src:TreeViewData x:Key="dataItems"/>

    <Style x:Key="TreeViewItemStyle1"  TargetType="TreeViewItem">
      <Setter Property="Foreground" Value="Navy"/>
      <Setter Property="FontStyle" Value="Italic"/>
    </Style>

    <Style x:Key="TreeViewItemStyle2"  TargetType="TreeViewItem">
      <Setter Property="Foreground" Value="Green"/>
      <Setter Property="FontWeight" Value="Bold"/>
    </Style>

    <src:TreeViewItemStyleSelector x:Key="tviSelector"/>
    
    <HierarchicalDataTemplate DataType="{x:Type src:ItemsForTreeView}"
                              ItemsSource="{Binding Path=SecondLevelItems}"
                              ItemContainerStyleSelector="{StaticResource tviSelector}">

      <!--Display the TopLevelName property in the first level.-->
      <TextBlock Text="{Binding Path=TopLevelName}"/>
      
      <!--Display each string in the SecondLevelItems property in
          the second level.-->
      <HierarchicalDataTemplate.ItemTemplate>
          <DataTemplate>
              <TextBlock Text="{Binding}"/>
          </DataTemplate>
      </HierarchicalDataTemplate.ItemTemplate>
      
    </HierarchicalDataTemplate>
  </StackPanel.Resources>

  <TreeView Height="200" ItemsSource="{Binding Source={StaticResource dataItems}}"
            VirtualizingStackPanel.IsVirtualizing="True">
    <TreeView.ItemContainerStyle>

      <!--Expand each TreeViewItem in the first level.-->
      <Style TargetType="TreeViewItem">
        <Setter Property="IsExpanded" Value="True"/>
      </Style>
    </TreeView.ItemContainerStyle>
  </TreeView>
</StackPanel>

Das folgende Beispiel zeigt den StyleSelector , der im vorherigen Beispiel verwendet wurde.The following example shows the StyleSelector that is used in the previous example.

public class TreeViewItemStyleSelector : StyleSelector
{
    public override Style SelectStyle(object item, DependencyObject container)
    {
        string itemString = item as string;

        string[] strings = itemString.Split(null);
        int value;
        
        if (!Int32.TryParse(strings[strings.Length - 1], out value))
        {
            return null;
        }

        StackPanel sp = ((Window1) Application.Current.MainWindow).sp1;

        if (value < 5)
        {
            return sp.FindResource("TreeViewItemStyle1") as Style;
        }
        else
        {
            return sp.FindResource("TreeViewItemStyle2") as Style;
        }

    }
}
Public Class TreeViewItemStyleSelector
    Inherits StyleSelector
    Public Overloads Overrides Function SelectStyle(ByVal item As Object, ByVal container As DependencyObject) As Style
        Dim itemString As String = TryCast(item, String)

        Dim strings As String() = itemString.Split(Nothing)
        Dim value As Integer

        If Not Int32.TryParse(strings(strings.Length - 1), value) Then
            Return Nothing
        End If

        Dim win1 As Window1 = CType(Application.Current.MainWindow, Window1)
        Dim sp As StackPanel = win1.sp1

        If value < 5 Then
            Return TryCast(sp.FindResource("TreeViewItemStyle1"), Style)
        Else
            Return TryCast(sp.FindResource("TreeViewItemStyle2"), Style)
        End If

    End Function
End Class

Im folgenden Beispiel werden die Daten erstellt, die im vorherigen Beispiel verwendet werden.The following example creates the data that is used in the previous example.

public class TreeViewData : ObservableCollection<ItemsForTreeView>
{

    public TreeViewData()
    {
        for (int i = 0; i < 100; ++i)
        {
            ItemsForTreeView item = new ItemsForTreeView();
            item.TopLevelName = "item " + i.ToString();
            Add(item);
        }
    }
}


public class ItemsForTreeView
{
    public string TopLevelName { get; set; }
    private ObservableCollection<string> level2Items;

    public ObservableCollection<string> SecondLevelItems
    {
        get 
        {
            if (level2Items == null)
            {
                level2Items = new ObservableCollection<string>();
            }
            return level2Items;
        }
    }

    public ItemsForTreeView()
    {
        for (int i = 0; i < 10; ++i)
        {
            SecondLevelItems.Add("Second Level " + i.ToString());
        }
    }
}
Public Class TreeViewData
    Inherits ObservableCollection(Of ItemsForTreeView)

    Public Sub New()
        For i As Integer = 0 To 99
            Dim item As New ItemsForTreeView()
            item.TopLevelName = "item " & i.ToString()
            Add(item)
        Next
    End Sub
End Class


Public Class ItemsForTreeView
    Private _TopLevelName As String
    Public Property TopLevelName() As String
        Get
            Return _TopLevelName
        End Get
        Set(ByVal value As String)
            _TopLevelName = value
        End Set
    End Property
    Private level2Items As ObservableCollection(Of String)

    Public ReadOnly Property SecondLevelItems() As ObservableCollection(Of String)
        Get
            If level2Items Is Nothing Then
                level2Items = New ObservableCollection(Of String)()
            End If
            Return level2Items
        End Get
    End Property

    Public Sub New()
        For i As Integer = 0 To 9
            SecondLevelItems.Add("Second Level " & i.ToString())
        Next
    End Sub
End Class

Hinweise

Mithilfe der ItemContainerStyle -Eigenschaft können Sie einen Stil festlegen, der sich auf die Darstellung der Elemente auswirkt, die die Datenelemente enthalten.You use the ItemContainerStyle property to set a style to affect the appearance of the elements that contain the data items. Beispielsweise TreeViewsind TreeViewItem die generierten Container-Steuerelemente Menufür die-Steuerelemente, MenuItem und sind-Steuerelemente.For example, for TreeView, the generated containers are TreeViewItem controls; for Menu, they are MenuItem controls. Wenn Sie mehr als einen Stil definiert haben und eine Logik angeben müssen, um auszuwählen, welche Anwendung angewendet werden soll, verwenden ItemContainerStyleSelector Sie die-Eigenschaft ItemContainerStyle anstelle der-Eigenschaft.If you have more than one style defined and need to supply logic to choose which one to apply, then you use the ItemContainerStyleSelector property instead of the ItemContainerStyle property. Beachten Sie, dass diese Eigenschaft ignoriert wird ItemContainerStyle , wenn die-Eigenschaft festgelegt ist.Note that this property is ignored if the ItemContainerStyle property is set.

Gilt für: