StyleSelector.SelectStyle(Object, DependencyObject) Method

public:
 virtual System::Windows::Style ^ SelectStyle(System::Object ^ item, System::Windows::DependencyObject ^ container);

public virtual System.Windows.Style SelectStyle (object item, System.Windows.DependencyObject container);

abstract member SelectStyle : obj * System.Windows.DependencyObject -> System.Windows.Style
override this.SelectStyle : obj * System.Windows.DependencyObject -> System.Windows.Style

Public Overridable Function SelectStyle (item As Object, container As DependencyObject) As Style

Parameters

Returns

Returns an application-specific style to apply; otherwise, null.

Examples

The following example shows how to define a StyleSelector that defines a Style for a row. This example defines the Background color according to the row index.

public class ListViewItemStyleSelector : StyleSelector
{
    public override Style SelectStyle(object item, 
        DependencyObject container)
    {
        Style st = new Style();
        st.TargetType = typeof(ListViewItem);
        Setter backGroundSetter = new Setter();
        backGroundSetter.Property = ListViewItem.BackgroundProperty;
        ListView listView = 
            ItemsControl.ItemsControlFromItemContainer(container) 
              as ListView;
        int index = 
            listView.ItemContainerGenerator.IndexFromContainer(container);
        if (index % 2 == 0)
        {
            backGroundSetter.Value = Brushes.LightBlue;
        }
        else
        {
            backGroundSetter.Value = Brushes.Beige;
        }
        st.Setters.Add(backGroundSetter);
        return st;
    }
}

Public Class ListViewItemStyleSelector
    Inherits StyleSelector
    Public Overrides Function SelectStyle(ByVal item As Object, ByVal container As DependencyObject) As Style
        Dim st As New Style()
        st.TargetType = GetType(ListViewItem)
        Dim backGroundSetter As New Setter()
        backGroundSetter.Property = ListViewItem.BackgroundProperty
        Dim listView As ListView = TryCast(ItemsControl.ItemsControlFromItemContainer(container), ListView)
        Dim index As Integer = listView.ItemContainerGenerator.IndexFromContainer(container)
        If index Mod 2 = 0 Then
            backGroundSetter.Value = Brushes.LightBlue
        Else
            backGroundSetter.Value = Brushes.Beige
        End If
        st.Setters.Add(backGroundSetter)
        Return st
    End Function
End Class

The following example shows how to define a ResourceKey for the StyleSelector. The namespc prefix maps to a CLR namespace and the corresponding assembly where the StyleSelector is defined. For more information, see XAML Namespaces and Namespace Mapping for WPF XAML.

<namespc:ListViewItemStyleSelector x:Key="myStyleSelector"/>

The following example shows how to set the ItemContainerStyleSelector property of a ListView to this StyleSelector resource.

<ListView 
      ItemsSource="{Binding Source={StaticResource EmployeeData}, 
                                        XPath=Employee}"
      ItemContainerStyleSelector="{DynamicResource myStyleSelector}" >      
  <ListView.View>
    <GridView>
      <GridViewColumn DisplayMemberBinding="{Binding XPath=FirstName}" 
                      Header="First Name" Width="120"/>
      <GridViewColumn DisplayMemberBinding="{Binding XPath=LastName}" 
                      Header="Last Name" Width="120"/>
      <GridViewColumn DisplayMemberBinding="{Binding XPath=FavoriteCity}" 
                      Header="Favorite City" Width="120"/>
    </GridView>
  </ListView.View>
</ListView>

For an example of how to create a selector to choose a defined style resource, see the implementation of DataTemplateSelector.SelectTemplate, which allows you to use custom logic to select a DataTemplate, based on a similar concept.

Remarks

To create a StyleSelector that applies a style based on custom logic, create a subclass of the StyleSelector class and implement the SelectStyle method.

Applies to

See also

• ItemContainerStyleSelector
• ContainerStyleSelector
• DataTemplateSelector